(CNN)"The Devil Wears Prada" just wouldn't be the same without Anne Hathaway.
But Hathaway, who played the lead role of Andy Sachs, a wide-eyed assistant to Meryl Streep's Miranda Priestly at a high-fashion glossy magazine, almost wasn't cast.
In a 15th anniverary oral history of the movie, the cast told Entertainment Weekly some behind-the-scenes secrets on the hit film.
Director David Frankel, who adapted Lauren Weisberger's massively successful book of the same name, said Streep was signed on, but they needed their Andy. Rachel McAdams, Scarlett Johansson, Natalie Portman, Kate Hudson and Kirsten Dunst were all on the list.
"We started negotiating with Annie to make a deal, and that didn't go well with the studio.... We offered it to Rachel McAdams three times. The studio was determined to have her, and she was determined not to do it," Frankel told EW.
Hathaway campaigned for the role, calling and visiting studio executives to try to convince them to give her the part.
"It spoke to me. It made me feel. It was about a subject that I take very seriously, but in such a wonderfully joyful and lighthearted way," Hathaway said of her character.
Frankel said it was Streep who convinced everyone Hathaway could pull it off.
"Meryl was eager to make the movie, and she said 'let me meet with her.' 'Brokeback Mountain' was about to come out. Annie had a wonderful, small role in that. And Meryl watched that scene from the movie, she met with her and called up Tom Rothman at Fox and said, 'Yeah, this girl's great, and I think we'll work well together,'" Frankel said.
When the call came, Hathaway said her answer was a no brainer.
"I patiently waited until it was my turn, and I got the call. It was the easiest yes in the world. I remember the moment I found out I got the part, I just ran screaming through my apartment. I had a bunch of friends over at the time, I just jumped up in the living room and screamed, 'I'm going to be in The Devil Wears Prada!'" she told the publication.