Singer Demi Lovato has opened up on cutting "toxic" people out of her life and revealed why she is no longer friends with her famous ex-boyfriends.

The 27-year-old has endured a tumultuous two years, including a near-fatal drug overdose and prolonged break from music.

She has dated a string of high-profile men, including actor Wilmer Valderrama and pop star Joe Jonas, and was known for being on good terms with her exes.

Lovato said the events of the previous two years made her realise staying in touch with former partners was not healthy.

Speaking on Jameela Jamil's I Weigh podcast, she said: "I've had to cut a lot of toxic people out of my life over the last year. I kind of used to have this mentality that if I had a negative experience with someone I always needed to mend it or I always needed to make things right.

"The fact of the matter is, I'm not really friends with any of my exes today because I had to realise that that wasn't healthy either. Trying to maintain close friendships with some of my exes just isn't realistic. There's actually a reason why people don't do that."

Lovato, a former Disney child star whose hits include Sorry Not Sorry and Cool For The Summer, added: "For so long people would be like, 'How are you still friends with your exes?' I'd be like, 'I don't know! I just am.' That was because I was afraid of fully letting go of people.

"Now that I've been able to fully let go of people, that is another thing I had to learn when it comes to cutting toxic people out of your life. If they're an ex, it's for a reason."

During her conversation with British actress and TV presenter Jamil, Lovato also reflected on the internet's so-called "cancel culture," where stars face calls for their careers to be ended over perceived missteps.

Lovato was on the receiving end recently when the hashtag #DemiIsOverParty was trending after she said she is no longer friends with fellow pop star Selena Gomez.

"One, it's not real," Lovato said. "I don't think anyone was ever officially cancelled, otherwise certain people wouldn't have Grammys, wouldn't have Oscars, certain people wouldn't be where they are in their positions."

Lovato added: "Where is the forgiveness culture?"