Just how does a Hollywood star in possession of an age-defying body and effortless style prepare for an action film?
‘I didn't really alter my diet and fitness regime but it’s funny, I was actually testing all the recipes for my book It’s All Good during the movie. They have these little kitchens in your trailer so I was able to cook at lunch and was eating well at the time.’
And yes, Gwyneth does cook for Iron Man co-star Robert Downey Jr – they are close friends on screen and off. ‘We have very good chemistry - we always have - it’s just one of those charmed partnerships. We really like being together and acting together. He’s like my brother, the ease with which we communicate on screen is just one of those natural things that happens sometimes.’
As for her character Pepper, Gwyneth is confident they too would get along if they met in real life. ‘I think Pepper and I would be fast friends. She’s a good girl, very tolerant, grounded, intelligent and understanding.’
When it comes to fashion, Gwyneth would love to raid Beyoncé’s wardrobe - ‘It’s amazing!’ But she’s also in love with contemporary British fashion. ‘There are so many amazing, emerging designers here in Britain. I think so far on this press tour, I’ve worn all British designers. I’m wearing Peter Pilotto today and wore Erdem for the Paris premiere.’
In the latest Iron Man installment Gwyneth gets to wear the Iron Man suit – another fashion moment of sorts - ‘I loved it. It was very empowering and a lot of fun. Plus, my son was thrilled.’

So, if she could choose one super power, what would it be? ‘I would clone myself, so that I could do two things at once!’
Gwyneth currently divides her time between LA, New York and London. Her favourite thing to do in the British capital? ‘Visit the parks. I think they’re the most beautiful parks in the world - so well planned and mapped out. You’re in the middle of the city but even the little squares are so lovely.’

Iron Man 3 is released on 25 April

See Gwyneth Paltrow's Style File