Comedian Russell seeming has only one look - black, skinny and slightly unkempt - so we can't wait to see how he brushes up for his big day.
As for Katy the possibilities are seemingly endless. Her stage costumes are, of course, renowned for their eye-popping and outlandish nature. We've seen her dressed as everything from a fried egg to a Christmas tree, not to mention sporting an impressive array of 1950s pin-up little shorts and dresses.
She was, however, sitting front row at some of the hottest shows during September's fashion week - she appeared at YSL, John Galliano, Jean Paul Gaultier and Fendi - so perhaps she'll opt for a dream designer dress.
But we're secretly hoping they may opt for West Ham themed wedding. Brand is a massive fan of the football club, and we recently spotted Katy wearing her own take on the strip.More