British movie star Henry Cavill has revealed his embarrassment at a time he accidentally got an “unacceptable” erection during filming of a sex scene for BBC period drama ‘The Tudors’.

The Hollywood heavy hitter was a part of the historical series based on the reign of Henry VIII, which ran for four seasons between 2007 and 2010. However, one particular moment left him mortified after a scene he shot with a girl with “spectacular breasts” made him rather aroused.

Henry CavillHenry Cavill was talking to Men's Fitness when he made the hilarious - and cringe-worthy - revelation

Recounting the cringe-worthy tale to Men’s Fitness, the 32 year old actor emphasised: “It's only happened to me once. 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.”

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Cavill said that he had to “apologise profusely” after the incident. “It's not great when you're in a professional acting environment and somebody gets a b***r is it?” he admitted. “No, not acceptable.”

Despite this, the Batman v Superman: Dawn of Justice star agrees with just about every other actor that there’s nothing remotely “sexy” about taking your clothes off in a room cluttered up by cameras, crew and lighting rigs.

“You don't think of sex scenes as showing your bum to the nation,” he said. “The actual physicality is very uncomfortable. All you're doing is smacking your n*ts against someone and nothing is going in.”

Cavill is the star of the imminently released spy movie The Man From U.N.C.L.E. before playing Superman alongside Ben Affleck’s Batman. He’s also rumoured to be playing a part in the Fifty Shades franchise, reportedly signing up last month for the sequel Fifty Shades Darker.

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