Anne Hathway Oscars 2013 Dress: Amanda Seyfried Tweets 'I Love You" After Valentino Dress Ditch

When Anne Hathaway learned that her Les Miserables co-star Amanda Seyfried's Oscar gown would be similar to the Valentino she planned to wear, she made a "difficult last-minute decision" to wear Prada instead. Hathaway reportedly saw Seyfried's Alexander McQueen dress after she showed her a picture of it on her iPhone during the Academy Award rehearsals on Saturday, Feb. 22.

"Anne was like 'WTF?!'" a source told Us. "She started throwing a fit!" The 30-year-old Best Supporting Actress winner, however, "never told Amanda she had to change the dress."

"I kind of can't understand why Anne didn't wear the Valentino gown, anyway," the source said. "She was the one winning the award, not Amanda. Who cares?"

Seyfried, who was reportedly thrown off by Hathaway's fit of anger, "didn't want to deal with it and left" the rehearsal, another second source revealed. "Anne made the fashion, make up, hair, and jewelry teams wait at her home for hours as she decided what to do about the dress debacle," the second insider told Us.

Seyfried wore an embroidered custom Alexander McQueen halter gown and her co-star, Anne Hathaway, may have been disappointed at her fashion choice.

The Devil Wears Prada star chose to wear a pale pink satin Prada gown instead of a custom dress made by Valentino. Hathaway told E! News host Ryan Seacrest that her dress was Prada and she "didn't know what she was wearing until three hours ago."

Valentino reportedly became disappointed about Hathaway's switch because the Italian fashion brand had sent out a press release ahead of the awards ceremony with a statement that she would be wearing one of their designs.

Hathaway released a statement on Feb. 27 that she made a "difficult last-minute decision" to wear the Prada gown instead of a Valentino and did not mention Seyfried in her statement.

"It came to my attention late Saturday night that there would be a dress worn to the Oscars that is remarkably similar to the Valentino I had intended to wear, and so I decided it was best for all involved to change my plans," Hathaway told Women's Wear Daily in a statement.

"Though I love the dress I did wear, it was a difficult last-minute decision as I had so looked forward to wearing Valentino in honor of the deep and meaningful relationship I have enjoyed with the house and with Valentino himself. I deeply regret any disappointment caused," she added.

On Saturday, a week after the fiasco, Seyfried tweeted to Hathaway: "Fact: I love you, Anne!"