Michael Cera had to 'lie down for half an hour' after being slapped by Rihanna

Michael Cera revealed that he needed to 'lie down for half an hour' after being slapped by Rihanna while filming a movie together.

Fans of Cera will likely recall the time he crossed paths with the 'We Found Love' singer on the set of the 2013 comedy film This Is the End, which saw the Superbad actor play a rather nasty fictionalised version of himself.

The film sees Cera rock up to a house party alongside the likes of James Franco, Jonah Hill and Seth Rogen, however, things take a turn for the worse when the apocalypse begins.

But before the group can experience the events of the rapture, they're enjoying a typical Hollywood house party, one which is attended by Rihanna.

In the scene in question, a coked-up 'Cera' spots the singer and can't resist the urge to slap her arse - a moment which was meant to be choreographed.

Michael Cera was truly committed to his role in 2013's This Is The End (Dimitrios Kambouris/Getty Images)

However, Cera was brave enough to ask the singer if he could slap her backside for real, to which the singer agreed – for a price.

"In the script, Michael Cera slaps Rihanna's ass and she doesn't hit him back," Rogan previously told Sway’s Universe.

“But he asked her, ‘Can I slap your ass for real?’ And she said, 'You can slap my ass for real if I can slap you back in the face for real'."

The pair performed 'three or four times' takes of the scene, with Rihanna slapping the actor every time.

Recalling the moment in an interview with GQ, Cera confirmed the singer 'definitely' hit him.

"But I really, I wanted that, you know," he continued, adding that a fake slap just doesn't look good' on screen.

The pair performed both slaps for real (Sony)

"I mean, I think it's a lot funnier and a lot more convincing. She really sent me flying, and it was great. And now it's on film forever, this pain that I experienced."

However, several takes of being slapped by Rihanna ultimately its toll on Cera, who ended up needing to lie down after being hit several times.

"She cupped his ear and actually whacked out his equilibrium, and he had to go lay down in his trailer for around half an hour," Rogan also recalled in his interview.

"That's the take we used in the movie. We didn't add any sound to that or anything," he added, revealing how the moment likely left Cera 'concussed, I think.'

Talk about dedication to the role.