Demi Lovato has insisted that she isn't dating One Direction star Niall Horan.

The US X Factor judge has been linked to the boyband singer since they struck up a friendship, but the internet has been buzzing with rumours of a romance despite Niall himself saying they are just "good friends".

Us Weekly reports that Demi, 20, has now commented on the speculation herself, saying the 19-year-old is "not my boyfriend".

She told Teen Vogue magazine: "He's a really awesome, sweet guy. But he's not my boyfriend... I'm in a place right now where I really need to focus on myself.

"Obviously, I'm still going to like people - or love them - but I need to not be in a relationship for a while because I need to be okay with being alone, first."

Disney actress Demi, who has suffered from bulimia, self-harming and depression in the past, also revealed she couldn't be happier with her life these days.

"I never thought it was possible to be happy because of how depressed I was my entire life," she said. "But I feel so incredible. It's like I'm living in a dream."