Rebel Wilson reported an unnamed male co-star after he asked her to pleasure him as his friends watched.

The Bridesmaids star reveals the actor told her to put her finger up his backside, while pals were filming her reaction on their cellphones.

In a new chat with British soldier and TV star Ant Middleton for his show Straight Talking, Rebel refused to name names and wouldn't discuss the project she was making at the time - but made it clear she didn't find the castmate's challenge remotely amusing.

"He asked me to put my finger up his a**e," the actress says. "Then he pulled down his pants and I was a bit entrapped in a room.

"I called my agent immediately and said this happened. We made an official complaint to the studio. But I'm such a professional that I was like, 'Well, I'm still going to continue with the job', which now I might not have."

Rebel, 40, didn't add any context and confessed she is still "scared" of naming the actor.