Sienna sets sights on Will

As well as everything else that's going on in her busy world, Sienna Miller, the fast-rising young actress, has a new man in her life - and his name is William.

As in Shakespeare, that is. She's hoping to star with the great stage actress Helen McCrory in a production of As You Like It later this spring.

'I can't wait,' Sienna told me excitedly.

'Fingers crossed that it will all work out,' she added.

She and her agents in London and Los Angeles are trying to work out dates with the producers of the film Factory Girl in which Sienna will portray Edie Sedgwick, the highborn Sixties party girl and model who befriended Andy Warhol and became his muse, posing for his photographs and appearing in his early movies.

If all can be agreed, then Sienna will play Celia who, while pretending to be a shepherdess, travels into the Forest of Arden with her cousin and best friend, the fiercely intelligent Rosalind. Ms McCrory will take on Rosalind, a part she was born to play.

'I did several plays when I was studying in New York, but I've always wanted to perform on stage in London and Celia is one of my favourite characters in Shakespeare,' Sienna told me.

It's a brilliant way for the 23-year-old to show what a fine actress she is.

'She's blonde, she's pretty, but boy can she act,' said Matthew Vaughn, who cast her in his directorial debut film, Layer Cake.

So far, most people know Sienna through her fiance Jude Law, whom she met on the set of the disappointing Alfie. Which is a shame because she got Layer Cake, Alfie and an as-yet-untitled movie about Casanova (opposite Heath Ledger) on her own acting merits.

If the dates can be agreed, David Lan would direct As You Like It for the London producer Sonia Friedman with award-winning designer Richard Hudson. It would open in late spring for a limited run at a theatre yet to be decided.