Jennifer Lopez bumped her head during Ryan Guzman love scene

Jennifer Lopez was left nursing a nasty bump on her head while filming The Boy Next Door after her co-star Ryan Guzman "threw" her in the air during a romantic scene.

The thriller's storyline required the superstar to get intimate with Guzman, but she reveals one part of the scene went horribly wrong as the young actor had no idea how light Lopez was.

During a joint appearance on Watch What Happens Live on Thursday (22Jan15), she explained, "There was one point in the filming where he had to lift me up... and we were filming in this old house... and he smashed my head into the ceiling."

Defending himself, Guzman said, "She's lighter than she seems! I just threw her up in the air!"

Lopez, who joked she was "light as a feather, like a marshmallow", added, "I think he thought, 'Damn, I'm gonna have to pick this heffer (heavy woman) up!' He went to pick me up and I went flying to the ceiling. My head got bumped!"

The movie stars Guzman as a teenage boy who becomes obsessed with his newly-single neighbour, portrayed by Lopez, after a one-night stand.