He was so impressed by her performance that he not only gave her the role immediately, but also re-wrote the part of single-mum Krista to make it more suitable for a younger actress. “The whole movie kind of hinges in a lot of ways on her performance, and I knew it was going to be the hardest part to cast," the Daily Star quoted him as telling Esquire magazine.
“This girl came in, and no one had said to me beforehand, 'Hey, look for this person". And obviously she was really attractive, and so I thought, 'Oh, here comes some blonde girl". She came in, did one reading, and just crushed it. I was sort of stunned. I said, 'Jeez, you know, that was really f**king good. Who are you?" She didn"t mention that she was on a television show. I just said, 'Look, there"s no alternative. I don"t have a second choice (in casting this role)"," he revealed.
And Affleck is also convinced that Lively has a big future in Hollywood. “I want to be on the record because I think she"s really going to blow up, and I want to look like the smart guy. I didn"t quite discover her, but at least I want to say I bought the stock when it wasn"t 500 dollars a share," he added.