Did Kate and William pay £20,000 for two tickets to the Ark Ball?

Tonight night the Duke and Duchess of Cambridge are going on their first big night out since they got married – and tickets for the charity event cost an eye-watering £10,000 each.

The annual Ark Dinner (it stands for Absolute Return for Kids) is one of the flashiest events on the London social calendar.

It takes place in a giant marquee on Perks' Fields, right behind Kensington Palace, and Kate and William will join 900 guests wearing evening dress and diamonds.

After drinks and canapés, guests will eat a gourmet dinner catered by exclusive catering firm Rhubarb. They will then watch a tear-jerking film and listen to William's first public speech as a married man, during which he will announce a new, high-profile collaboration between Ark, which provides assistance for some of the world's poorest children, and the Princes' Foundation.

DJ Mark Ronson will then get everyone dancing before the celebrity auction and lottery begins.

Last year partygoers bought lottery tickets at £5,000 each for a chance to win a Vespa decorated by designer Marc Newson.

The auction raised even more money when a Richard Price photograph fetched £260,000, a Fiat 500 car painted by Damien Hirst went for £90,000 and a week on a private yacht donated by Elisabeth Murdoch and Matthew Freud attracted a winning bid of £310,000.

In total, the 2010 event raised more than £14million.

The charity was founded by Swiss financier Arpad 'Arki' Busson, who has two children with Elle Macpherson and an on-off relationship with actress Uma Thurman.

We can't help but wonder if Kate and William will be joining in – unless, of course, they're donating a prize themselves...