With such a close relationship with the Italian designer, who dressed her previously for the Oscars in 2011 and then designed her one-of-a-kind wedding gown, it was sure-in that she would be wearing something from him.
The Les Miserables actress has released a statement as to the dress choice she made, explaining that another attendee was set to wear a very similar gown.
Maison Valentino released a statement just hours before the ceremony revealing that they would be dressing Anne in Couture, as well as Jennifer Aniston and Sally Field - both of whom looked beautiful.
Anne told the press when she arrived at the event: "I didn't know what I was wearing until two hours ago. I tried on a lot of dresses, but at the end of the day I loved the simplicity of it."
An official statement was released last night by Anne's publicist, to set the record straight.
"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," explained Anne.
"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 honour of the deep and meaningful relationship I have enjoyed with the house and Valentino himself. I deeply regret any disappointment caused."
Anybody else dying to know which dress it was?
Apparently, rumours are floating around that it was in fact the lilac Alexander McQueen embellished gown that co-star Amanda Seyfried wore to the event.
Maybe one day soon, she'll have another event to wear it to and we'll get to see what it looks like.
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