Keira and Sienna are beachy keen on each other

Sienna was cast as the wife of Dylan Thomas after Lindsay Lohan pulled out of the movie

She recently told Elle magazine: "I wish I was Sienna Miller."

"At the parties, I stand on my own, grinning aimlessly. I can never think of a thing to say. I watch that girl and she’s just fabulous. She talks to everyone and laughs and smiles and looks as if she is genuinely enjoying herself.

"When I talk to her I hope a bit of her party personality will rub off on me, but it never does. She could give master classes in being the most amazing party guest."