This interview first ran in the December 2012 issue of ELLE.

SPILLED DRINKS. Honking, table-thumping, barman-scaring laughter. A mention of a (male) co-star's, uh, appendage. A hunger for pork scratchings. More laughter. More spillage. Another round of drinks. And it's still light outside. HONESTLY, you can't take CAMERON DIAZ ANYWHERE.

A session in the boozer with ELLE's favourite Hollywood powerhouse was always going to be fun. As we've known pretty much since the dawn of her career – in The Mask, all of 18 years ago – few icons can do humour, drama, melodrama, stuntwork, dancing and proper acting as well as Cameron. She's an all-round all-star actress.

We knew she'd be up for joining us in a central London pub – no boring, old, overstuffed, under-stimulating, bland, PR-approved hotel interview suite for Cameron. She turns up with the minimum of fuss and film-company entourage – despite the fact she's partly here to promote her new movie, Gambit, in which she stars alongside Colin Firth – but she's smart enough, experienced enough and, yes, old enough to handle herself.

But we've thrown Cameron a curveball. We're inducting her into the world of The Great British Pub Quiz.

'What?' the 5ft 9in 40-year-old shrieks, wobbling on her Stella McCartney high-heeled sandals, long-tall-Cam almost bumping her head on the low ceiling of this 300-year-old coaching house. 'I do terrible at testing at anything. That's why I hated school.'

I knew that Cam leapt straight from school in Long Beach, California, to, at 16, a successful modelling career. But what academic qualifications did she leave with?

'Nothing! What's a qualification?' she jokes. 'I did graduate but I honestly have no idea how. I don't think I ever did one day of work in school.'

So if this whole acting thing hadn't worked out – if Charlie's Angels, There's Something About Mary, Danny Boyle (A Life Less Ordinary) and Martin Scorsese (Gangs of New York) hadn't come calling – what would she be doing now?

'I have no idea. That's why I'm so grateful for it. It's the only thing that I know how to do. I do think about it all the time – what would have happened had I not just found my way out from that? But I think you always find your way out.'

Except, it seems, from the first ever ELLE Pub Quiz... It pains me to report that Cam Diaz might be an A-list star but she's an F-grade trivia head.

First round: British Pub Culture. Ms Diaz, we are in the famous Punchbowl pub in Mayfair, London. Who owns the joint?

'I have no idea.'

It's Guy Ritchie.

'Oh, is it?' she says. 'I didn't realise that. I feel very honoured to be in Mr Ritchie's pub. See, I already failed the first question. But let me ask you: does he know that I'm here?'

I don't think so.

'See!' comes Cam's triumphant, point-scoring shout. 'Just because both of us are in the movie world doesn't mean we track each other!'

'This is way too hard! Um, Black Sabbath is a band, so it's not a beer.'

Yeah, whatever. Question two: which of these is not a brand of British beer: Theakston's Old Peculier, Timothy Taylor's Landlord, Bradley Wiggins' Leathery Saddle, Worthington's White Shield or Brunswick Black Sabbath?

'This is way too hard! Um, Black Sabbath is a band, so it's not a beer.'

Wrong. It is also a beer. Bradley Wiggins isn't, though. He's Britain's Olympic and Tour de France-winning cycling hero.

'The leathery saddle sounded so convincing! Alright, so I didn't follow the Tour de France this year,' she adds, sarcastically. 'And, honestly, names to me – I forget names quicker than they're actually spoken to me. Literally, it's like a form of dyslexia. I cannot remember names or titles at all – books or movies or beers or wines or anything that should be relevant in my life. Let's make up a name for the condition – are you clever enough? I'm not.'

Well, it's not dyslexia, or dsypraxia... Dufus-itis?

'Yeah! The feeling when I'm trying to remember a name is a total emptiness. It's something that's been with me for a long ime. I used to remember people by their haircuts. I'm a visual person. But now I have so many faces that I meet on a daily basis that I can't capture all of them.'

I used to remember people by their haircuts. I'm a visual person. But now I have so many faces that I meet on a daily basis that I can't capture all of them.'

So on the London set of your current project, Ridley Scott's The Counselor, you're looking at Brad Pitt, going...

'Yeah, "Hmm, I know. I know you! Your hair's a little longer, that's all..."'

Dressed down in a faded Levi's denim jacket, dressed up in Stella McCartney 'jodhpurs-come-trackpants', sparkling with a double diamond ring (not, to be clear, on her wedding finger), Cameron clatters into the pub on her day off. She's immediately chatty, instantly relaxed, hugely grateful to the chef for sending in some canapés, and very apologetic for being a not-unreasonable 30 minutes late.

She's primarily in London to make The Counselor. It's the first film she's shot this year, and so this avowed hotel-hopping nomad has been enjoying more home time than usual. She's been living at her recently made-over New York apartment, and working on her new Los Angeles base, a Beverly Hills mansion that she bought in 2010.

'This past year, I've been in LA mostly redoing that property and making it really homey. Before, it was just a disaster, boxes everywhere, nowhere for anybody to sit. And I really got to enjoy it this summer with family and friends. Half of it's done now. That part is really dialled in – we're sweet! That s*** is slammin',' she beams, adopting her mega-watt party-girl persona.

But your bedroom is, what, a shed?

'My bedroom is gutted at the moment,' she nods, half embarrassed, half sad. 'I'm sleeping in the guest room. But once that's done, I will have a fully renovated home. So I'm very excited.'

The Counselor is a thriller involving a suitcase full of cocaine and a starry cast: Diaz, Pitt, Penélope Cruz, Javier Bardem and Michael Fassbender. To the nudge-nudge quiz question, 'What is Fassbender's most famous part?', Cameron replies that, actually, she hasn't seen him in Shame, in which Fassbender memorably appeared naked. But she knows of what I speak. 'Well,' she says coquettishly, 'he does have a lot of confidence...'

But she is also in town to promote Gambit, which was shot here, too. The comedy was scripted by the Coen Brothers, and is based on a 1966 British art-heist caper that starred Michael Caine and Shirley MacLaine in the roles now played by Firth and Diaz. The actress has a lot of fun onscreen, playing a Texas cowgirl who is persuaded by Firth's prim painting expert to help him defraud his loathsome media baron boss (Alan Rickman) with a fake Monet created by a twinkly gentleman forger.

The latter part is played by veteran British actor Tom Courtenay, 75, 'Who I'm in love with,' sighs Cameron, who last year split with baseball player Alex Rodriguez and to all appearances seems to still be single. 'I need a little bit of hocus-pocus magic voodoo to try get him to be, like, 40 years younger. He's so charming, so much fun – he's got such a great spirit.'

When I suggest she get a DVD of 1963's Billy Liar – the classic Brit film starring a beautiful young Courtenay – she positively shivers. 'I don't want to – my heart would break. Like, literally. I don't want to tease myself [with] what could have been...' Cameron consoles herself with another sip of the pint of iced tea that she's made for herself using her own bags of white tea (not, we have to admit, widely available in most London boozers, which is why she's brought her own) and the pub's biggest jug of ice. 'I'm just spilling it all over the place,' she frowns as the cubes clatter into her glass. 'Congratulations, Cameron,' she mutters. 'This decanter is really crampin' ma steez...'

Time, then, for another couple of questions about British pub culture.

What are pork scratchings made from?

'I could possibly go with some part of the hoof, but then it's maybe what the pig scratches off – so could it be skin? Yes? Oh, that's my favourite snack in the whole world! Even with the bristles – I don't care, I'll do it. Every day I'd eat that as a child; I teethed on it! It's called chicharrón, it's a Cuban-style snack. [Cameron's father's family are Cuban.] They deep-fry the pigskin and fat, and you chew on it, and it gets all stuck in your teeth, and you have to suck it off – it's really amazing. It's my favourite thing,' she sighs. 'Do they have it on the menu here?'

Doubt it. But, question, if they had Lancashire hotpot, what would you expect to be in it?

'Ooh, let me see, a hotpot,' she purrs lasciviously. 'I don't even want to let you know where my mind went with that. Sexual? No, it was more sophomoric – yes, the toilet! I have a tendency to either one or the other: sexual or scatological... But I've tried to become a little more mature. Is it anything to do with sausages?' she giggles, waggling her eyebrows. 'I've had sausage before... in a hotpot!'

'Is it anything to do with sausages?'

Her enthusiasm for artery-clogging – and, frankly, foul – pub snacks aside, these days Cameron is all about good nutrition. She's been a fitness freak since her twenties, her famously lean, toned and glowingly healthy physique the product of a daily pre-breakfast gym routine. But now she's preparing to go a few steps further.

This winter she's writing a book about food, diet and general well-being. Central to her philosophy is the idea of women controlling what they consume, in a positive, healthy way.

I'm excited about my discipline,' she says of her fitness and nourishment regime, which revolves around 'a protein, a grain and a green... I want to be disciplined. It's not a limitation to me; it opens up my life to so many other opportunities.'

Cameron wants people to understand the science of food, the health-ruining and life-threatening peril of empty calories, and the need to take charge of their meal-time habits. And she's leading by example.

'If I'm out for the day, running around taking care of errands, especially in Los Angeles, most of the time I show up with my own food. It's my body – I don't have to have somebody else make the choices for me. So I take it with me, and I set up my life so that I can do that. I've built it into my schedule so that I have food that I can just grab out of the refrigerator and pop into my cold pack and take it with me for the day. I'm a woman,' she shrugs, 'I carry a purse, so another bag is not really a big deal.'

I ask what it is she takes with her. But – wary perhaps of inspiring 'Cameron eats this, so that's exactly what I must eat, too' reactions – she won't say. 'The book isn't about me. It's not about what I eat or do what I do. It's really about the information, so that young girls and women can look at it and make their own choices. I'd hate to give them guidelines of what I do. My hope is that I give them all the information so that it doesn't matter what I or other people do.'

And it's not, she insists, about self-flagellating denial for its own sake.

'It's about controlling something so that you can have more. With good nutrition you actually get to eat more food. 'Cause when you're eating empty calories, a massive plate of food that does nothing for you, all it does is feed sickness, heart disease, diabetes, obesity, high blood pressure, lethargy, issues with your digestive system...'

She could go on, and she does, at length, with eyes-wide passion for a project that she hopes will hit bookshops next September. But the clock is ticking, and last orders will soon be called. She may have displayed detailed knowledge and enthusiasm for how women can enhance their lives through improved nutrition, but what does she really know about, say, weight loss?

What burns most calories – 30 minutes of dancing or 30 minutes of sex?

'Ha ha ha! Depends on what kind of sex you're having! Try 'em both! Do them both on the same day, that's what I say.'

Apparently it's 85 calories for the sex, 130 for the dancing.

'Well, there you go, just add it up! I say burn calories whatever way you please!'

What has the most calories, a 100ml glass of wine or a 100g bar of chocolate?

'That's a trick question, right? So probably wine 'cause of the way it turns to sugar in your body...'

Seemingly, there are 74 calories in the wine, but 520 calories in the chocolate.

'OK, that's a huge difference! But if it's dark, dark chocolate, that's a superfood – the cocoa is a superfood. Don't waste your time with all the sugary milk chocolate.'

'dark, dark chocolate, that's a superfood – the cocoa is a superfood. Don't waste your time with all the sugary milk chocolate.'

So, how has our contestant fared in the inaugural ELLE Pub Quiz? Not great, to be honest. That inability to remember names wasn't a big help. But, also, she's not at the top of her quiz game. When Cameron is on a filming job, like she is now, she gives it her all. Making movies – and not any of the ancillary celebrity shizzle – is how she gets her buzz.

'See,' she says, 'if you'd told me I needed to have answers, I would have showed up with some sort of knowledge. But since I'm on a movie and I have solely reserved all of my brain power for that project, I just came here ready to spew the same old s***, ha ha ha!' laughs too-honest, too-cool, too-smart Cameron Diaz.

So, I think, let's throw her a bone. Let's end on some easy-peasy quickfire fashion questions. To which Cameron responds with the confession that, 'Oh God,this is where I really suck.'

Who designed Kate Middleton's wedding dress?

'The label was Alexander McQueen. But I don't know the name of the actual designer...'

Oh, yes, that name thing again. Question two: what are the professions of Paul McCartney's three adult children? 'Photographer, musician and designer. Some things I might know, about people I care about!' Diaz says in a sing-song, na-na-na-na-na voice. 'I know Stella,' she says. 'She's rad, she's so awesome. She really cares, [designing is] her passion, she loves it, she puts her heart and soul into it. She's created such a great brand. And I think she really stands alone. And she doesn't stop! And she has four children. And a really handsome husband! And she's such a hands-on mum, too. She's super- woman. You know how she does it? She has real love for what he does. She's always happy; she always has so much joy in her.' Is that the same for Cameron?

'She's rad, she's so awesome. She really cares, [designing is] her passion, she loves it, she puts her heart and soul into it.'

'I feel so fortunate that I get to do what I do,' she says.

'You want to do your best. The truth of the matter is,' she says, 'that we can really do anything we want to do. We're only limited by the limits we put on ourselves. With scheduling, I have that mentality that someone like Stella has. If you guys can make it fit into the schedule, somehow, then I can do it. If it can be done, I'll show up, and I'll give it my all.'

Even, it seems, if there are trivia-related questions involved.

OK, final question on film. Which should be a specialist subject. Can you name three James Bonds?

'Sean Connery. Pierce Brosnan. And our lovely, young... um... Oh, I know his haircut! He's on the cover of a film magazine right now... Ah, uh... and he's so handsome! He's married to... Ah, Craig!... Daniel Craig!'

Phew.