Ed Westwick has strongly denied claims he raped a second actress.
In a tweet he said he has "absolutely not" raped anybody, and that he is cooperating with authorities to clear his name "as soon as possible".
On Wednesday Aurelie Wynn posted on Facebook, claiming she was raped by the actor at his home.
It came a few days after actress Kristina Cohen also accused him of sexually assaulting her three years ago.
Writing on Twitter, Ed said the two claims were "unverified" and "provably untrue".
Aurelie claimed the rape happened after she was invited to a place he was renting in August 2014.
"I said 'no' and he pushed me face down and was powerless under his weight.
"I was wearing a one piece bathing suit that he ripped, I was in complete shock, I am also very tiny," she posted.
She said she had the courage to speak out after actress Kristina Cohen also accused the actor of rape.
In her Facebook post, Kristina claimed she'd gone to Ed's house with her then-boyfriend and was napping in his guest room.
"I was woken up abruptly by Ed on top of me.
"I told him to stop, but he was strong. I fought him off as hard as I could but he grabbed my face in his hands, shaking me," she wrote.
But the 30-year-old said he doesn't know her, and denies the attack.
Police in LA have said they're investigating a rape allegation made against the actor.
Two BBC shows starring Ed Westwick have been put on hold in light of the allegations.
Agatha Christie's Ordeal by Innocence, due to be on BBC One at Christmas and the BBC Two comedy, White Gold.
Newsbeat has contacted Ed Westwick's lawyer for further comment.