Nick Jonas was "genuinely concerned" he'd lose Demi Lovato.

He told Entertainment Weekly magazine: "It’s been years of working on herself and getting better, but she’s amazing - and a better singer, too, because she’s healthy. But I was genuinely concerned that I might lose my friend."

And the 23-year-old previously opened up about the "real and genuine" chemistry he has with the 'Cool for the Summer' singer.

He shared: "We've always had very open communication and we're very honest with one another. There's also a real and genuine comfort level between us. And I think a lot of our chemistry comes from that.

"She has been very close friend and business partner for nearly ten years. I'm in constant awe of how powerful her voice is and in my opinion she's truly one of the most talented artists out there."

The pair - who have their own record label - are heading out on tour together and Nick has revealed Demi has been very "hands on" about organising the show.

He added: "We're really putting everything in to this tour and working with some of the best in the business to bring our visions to life. Demi and I both tend to be very hands on with anything that we're a part of, so we sit in on every creative meetings and we each come to the table with ideas.

"The idea of Future Now will come to life in a way that we want the fans who come to these shows to feel like they're a part of something unexpected and special from the moment they walk in to the venue till the moment they leave."