Courteney Cox has revealed her husband was told off by a hospital patient for watching what appeared to be a home sex tape.

David Arquette was editing an episode of Cox's TV drama Dirt in a hospital waiting room after his mother-in-law was admitted for open-heart surgery.

Arquette was working on the episode he directed when a patient came over and asked him what he was doing.

"We were in the hospitality suite... and David's watching the computer [of] his cut and giving notes from Cleveland," Cox explained. "There was this part he was watching, where there was like a home sex video.

"He was really into it... and this woman walks by, looks over his shoulder and says, 'What are you doing?' [She thought] he was just sitting in the hospitality suite enjoying some sex show."