Advertised Extra: Emma Watson got prominent billing in the advertising, clearly hoping to draw in some of her Harry Potter fans. Lucy is a minor character who's mainly in the first act, disappears and then reappears briefly at the end.
Scarlett Johansson was the first choice to play Marilyn but turned it down. Kate Hudson and Amy Adams were also considered.
Catherine Zeta Jones was the first choice for Vivien Leigh. But she declined to spend more time with her husband. Rachel Weisz was the second choice, but she was too busy with other projects - and so Julia Ormond was cast.