“That’s the thing about corsets,†Keira Knightley mumbles to her agent. “Just when you thought you were out, they pull you back in.†Knightley, who recently appeared as 19th-century French heroine Thérèse Raquin on Broadway, is in talks to play 18th-century Russian monarch Catherine the Great in Barbra Streisand’s biopic about the Russian ruler. With a script from Kristina Lauren Anderson, the drama will center on Catherine’s abusive marriage to Emperor Peter III and later rise to power. Though it might be fun to draw a quick comparison between this role and Knightley’s turn as another Russian woman in Joe Wright’s Anna Karenina (a far better movie than you remember!), it’s important to remember that Catherine was actually born to a German ruling family — you know, just to feel superior about things.