“I’d be completely flattered to be compared to Scarlett Johansson. I don’t think I’d come off particularly well, but I understand that. She’s a sensational actress.”—Keira Knightley being adorably sweet when asked about her “rivals”.
“Scarlett isn’t like her character at all, because she’s so funny and delightful. She’s always in a good mood and is just a riot. Black Widow has a darker incarnation in this film than she did in ‘Iron Man 2’ and Scarlett is very precise when she acts. We hint a little bit at her back-story and it isn’t pretty”—
Joss Whedon on Scarlett Johansson and her portrayal of the Black Widow