Trending: Playing a cinematic great? it's a tough act to follow, Scarlett

Scarlett Johansson as Janet Leigh

It has just been announced that Johansson is to play the Psycho star in a film about Alfred Hitchcock, which beggars the question: is there a more intimidating role to take on than that of another celebrated actor? You'll likely clean up come awards season, but who's going to play Meryl?

Michelle Williams as Marilyn Monroe

A less confident actress would balk at the idea of playing the sexiest woman of all time. Williams wiggled and giggled her way to an Oscar nomination.

Robert Downey Jr as Charlie Chaplin

The troubled star learnt how to play the violin and tennis left-handed before taking on the role of the silent film star. It secured him his first Oscar nod.

Cate Blanchett as Katharine Hepburn

Martin Scorcese had Blanchett watch all of Hepburn's work before filming The Aviator. She nailed the accent and took home the Best Supporting Actress Oscar.

James Franco as James Dean

With such chiselled good looks, Franco was a natural choice to play the lead role in the TV movie James Dean. He won a Golden Globe for his moody portrayal.