Sienna Miller loved wearing corsets in new movie ''Casanova'' - because they gave her big breasts.

The blonde actress - who is romancing heartthrob actor Jude Law, says she was happy to squeeze into the painful girdles when she realized how much they enhanced her assets.

Sienna - who plays Casanova's lover, Francesca, in the film - said: "I got to wear corsets in the movie. They are so romantic, they look fantastic, although they are agony. They squeeze you to within an inch of your life."

The 23-year-old star added to Britain's New magazine: "I loved the cleavage, though. I never realized I had breasts until the movie. I was thrilled."