sienna millerSienna Miller has revealed it was hard acting opposite Keira Knightley in The Edge of Love because her character is a bit of a frump.

Sienna had to gain weight to play the role of Caitlin, Welsh poet Dylan Thomas’ wife, in the period piece and she told Elle magazine recently: “Then I had to face seeing myself alongside Keira, who is the most beautiful woman in the world.”

“The big thing I’ve discovered [though], the big secret, is that it’s all about how happy you are.

“People forget your flaws and imperfections if they see you’re happy.”

She added that she and Keira would frequently “sit there and moan to each other”: “But then after a few hours I’d burst out laughing because, ultimately, we both love our jobs and are incredibly privileged to have these lives.”