Liam Hemsworth pranked on Paranoia set

Australian actor Liam Hemsworth fell victim to a rude prank while filming a steamy scene for new movie Paranoia as co-workers put a sex toy in the bed.

The Hunger Games star strips off with his co-star Amber Heard in the film, but the actor was left red-faced when he went to grab what he thought was the actress' arm, but in fact turned out to be a "giant dildo".

He tells E! News, "I get into the bed and they say 'action'. And then I turn over and I grab what I thought was (Amber's) arm, and it was a giant dildo. It was... big, a black one. And I pulled it out, and everyone was in on it (the joke)... except me, yeah."