Henry Cavill has admitted that he once got an erection shooting a sex scene.

The actor told Men's Fitness that he had a "very embarrassing" moment during his time on The Tudors, when an actress with "spectacular breasts" got him a little bit too excited.

"It's only happened to me once, and it was very embarrassing," he said. "A girl had to be on top of me, she had spectacular breasts, and I hadn't rearranged my... stuff into a harmless position.

"She's basically rubbing herself all over me and, um, it got a bit hard."

He added: "I had to apologise profusely afterward. It's not great when you're in a professional acting environment and somebody gets a boner, is it? No, not acceptable."

Despite the incident, Cavill said that sex scenes are "acutely uncomfortable".

"The very last thing it is is sexy," he said. "The actual physicality is very uncomfortable. All you're doing is smacking your nuts against someone, and nothing is going in."