Matt Damon never denied rumours he was gay because he didn't want to insult his friends.
The 42-year-old actor - who is happily married to wife of seven years Luciana, with whom he is raising four daughters - said the constant speculation about his sexuality put him in a strange position because he didn't want to offend anyone.
He told Playboy magazine: "I never denied those rumours because I was offended and didn't want to offend my friends who were gay - as if being gay were some kind of f..king disease. It put me in a weird position in that sense. The whole thing was just gross."
The rumours started when Damon - who previously dated Minnie Driver and Wynonna Ryder - released the Oscar winning movie Good Will Hunting with best pal Ben Affleck in 1997.
But he insists it hasn't affected his career and didn't make him reconsider kissing his co-star Michael Douglas in their upcoming HBO movie Behind the Candelabra about flamboyant pianist Liberace.
He said: "We both have a lot of gay friends and we were not going to screw this up or bulls..t it.
"It wasn't the most natural thing in the world to do, though. Like, for one scene, I had to come out of a pool, go over to Michael, straddle him on a chaise longue and start kissing him.
"And throughout the script, it's not like I kiss him just once. We drew it up like a football plan. Michael was a wonderful kisser."
Damon also picked up kissing tips from the late Heath Ledger, who told him he "drank a half a case of beer" before kissing his co-star Jake Gyllenhaal before kissing him in Brokeback Mountain.