One Direction star Harry Styles has answered questions on his sexuality, insisting "I'm pretty sure I'm not bisexual".

The 19-year-old pin-up and his bandmates all posed for their own cover photos for GQ magazine, and in an interview Harry was asked about his rumoured relationship with Radio 1 DJ Nick Grimshaw.

Harry asked: "What rumours would they be?" Pressed to address the rumours he and Nick, 28, are lovers he said: "Oh, really? I didn't even know. We're not dating, no. We're just friends."

Asked directly about his sexuality Harry said: "Bisexual? Me? I don't think so. I'm pretty sure I'm not."

But he admitted the rumours could be annoying.

"Some of them are funny. Some of them are ridiculous. Some of them are annoying. I don't want to be one of those people that complains about the rumours. I never like it when a celebrity goes on Twitter and says: 'This isn't true!' It is what it is; I tend not to do that.

"The only time it gets really annoying is that if you get into a relationship and you get into a place where you really like someone and then things are being written in the papers that affect them and how they see you. Then it can get annoying."

There have also be rumours Harry and bandmate Louis Tomlinson are secret lovers, with fans dubbing them 'Larry Stylinson'.

Asked if it is hard to stay faithful to girlfriends when fans are throwing themselves at the boys all the time, Louis said: "The type of girls that would sleep with you in a heartbeat aren't the type of girls I'd want to take home anyway."

The full interview is available in the September issue of GQ on sale on Thursday August 1.