To us, willowy Keira Knightley looks as if she spends more time jogging at the spa than running a salon. No matter, she's the go-to gal for period melodrama: early 20th century for Atonement, the 19th for Pride and Prejudice, 17th for the Pirates of the Caribbean trilogy. She's back in Masterpiece Multiplex territory with this fact-based story of 18th century vixen Georgiana Cavendish, whose beauty and wiles were the inspiration for the Lady Teazle character in Sheridan's The Rivals. Ralph Fiennes is Georgiana's dissolute hubby; Dominic Cooper (the bridegroom in Mamma Mia!) plays the young swain into whose arms she falls.
— Richard Corliss