Actor Michael Cera has revealed that working with Bajan beauty Rihanna on his new film, This Is The End, was a painful experience because it was in the script that she had to slap him.

The movie, which is an armageddon-style comedy featuring a host of celebrities playing themselves, sees the 'Umbrella' superstar smack Cera across the face in a fit of rage and he told Rolling Stone magazine that she put her back into it:

"I mean, she hit me hard, but it was like what it feels like to get hit hard. I encouraged her to do it, though. I wanted her to hit me really hard."

Earlier this year, Cera's co-star Seth Rogen joked that after a few takes of that particular scene he had to yell 'cut' because of the pain:

"Rihanna did slap the s**t out of him. For real, he said, 'I'm actually going to slap the s**t out of your a**,' and she was like, 'I'm actually going to slap the s**t out of your face then.' We did it like six times, and the last time, he was like, 'I don't think I can do this anymore.'"

Watch Rogen discuss the much talked about slap here: