The actress, who has appeared in more than 50 films, said that she met Weinstein at the after party of the 2008 ceremony while she was working as a spokeswoman for LG, reports The Guardian.
While speaking at a press conference, Malthe said that despite her repeatedly telling Weinstein she was not interested in a sexual relationship, he forced himself on her in a room at the Sanderson hotel after they met at the Baftas in February 2008.
She said, "I was sitting on the bed talking to Harvey when he pushed me back and forced himself onto me. It was not consensual. He did not use a condom. I was completely grossed out. I believe that I disassociated during the time that he was having sex with me. I laid still and closed my eyes and just wanted it to end. I was like a dead person. Afterwards I lay there in complete disgust."
The next day she received a script, she alleged, before returning to Los Angeles where she said she was given the impression she had landed a role in the movie 'Nine', a film produced by Weinstein that would star Daniel Day-Lewis, Nicole Kidman and Judi Dench.
Malthe's lawyer Gloria Allred, who appeared alongside Malthe, described it as sexual assault that involved non-consensual penetration.
The actress also claimed that she was asked to do a threesome with Weinstein and another woman. She refused and when she later called him to say a role in a movie was not worth it, he became angry and called her an "ungrateful c***".
"I had experienced sexual harassment from other powerful men in Hollywood, but my experiences with Harvey were the worst," noted Malthe.
Malthe, who is from Norway, said she left the U.S. after that incident and became depressed and anxious. "I felt that my dreams had been shattered," Malthe said.
The allegations follow weeks of claims about Weinstein.
Many Hollywood actresses including Angelina Jolie and Gwyneth Paltrow have come out with the claims that the movie mogul tried to sexually harass them.
The Weinstein Company, which sacked Weinstein, is also being sued for five million dollars by actress Dominique Huett, who claims the studio was negligent for having knowledge of his behaviour. (ANI)