Jake Gyllenhaal refuses to wear underwear when filming sex scenes.

The 29-year-old actor - who is currently dating 21-year-old country singer Taylor Swift - was happy to get naked for his role in movie 'Love & Other Drugs' because he believes the audience needed to see him without clothes to believe his relationship with co-star Anne Hathaway's character was real.

He said: "If we were going to be as open and intimate in a love story as we could be we have to do the same thing with sex.

"When you see two people in a movie like that, particularly as an actor, and they are portraying two people in love, it's like, how do you even unconsciously believe people are in love if they don't want to be naked around each other.

"I don't know about you guys but I've never had sex with underwear on and it's an odd thing to watch an actor do. You can try but I wouldn't recommend it! So that was really important. We knew that if we did we would get somewhere in the audiences' unconscious that these were people who were actually in love and not just actors telling a love story."

The Hollywood hunk wasn't scared about getting nude and didn't consider working out any harder at the gym for the role of pharmaceutical rep' Jamie Randall.

He added to BANG Showbiz: "We really didn't think about getting in shape. I wanted him to be a little skinny and sinewy and slimy."