Demi Lovato and Wilmer Valderrama split

Demi Lovato and Wilmer Valderrama have called it quits after six years together.

The 23-year-old Cool for The Summer hitmaker, along with her 36-year-old actor boyfriend, posted a joint statement on Instagram late on Friday (03Jun16), announcing they had parted ways.

"After almost 6 loving and wonderful years together, we have decided to end our relationship," they wrote. "This was an incredibly difficult decision for both of us, but we have realized more than anything that we are better as best friends.

"We will always be supportive of one another. Thank you to everyone who has offered us kindness and support over the years. With only love, Wilmer & Demi."

The couple was last seen together at a red carpet event at the Billboard Music Awards in Las Vegas, Nevada, on 22 May (16), and later spotted going out for dinner in Beverly Hills, California, just two days later.

Rumours had recently swirled of a possible engagement, and back in February (16), she told Ellen DeGeneres on her U.S. talk show that despite no ring, she was in the relationship for the long-haul.

"We've been together this long... obviously I'm not going anywhere," she said.

Wilmer, best known for his role as Fez in That '70s Show, spoke fondly of his superstar girlfriend back in January (16), and told Entertainment Tonight their bond was beautiful: "You know, we've been best friends for about six years. We haven't necessarily been dating for six years, but we have six years of friendship, and it's been beautiful," he said.

Demi also spoke openly about the couple's relationship in the recent issue of Latino magazine, where she revealed she felt blessed to be dating the actor, who she has previously praised for supporting her through her battles with drugs and an eating disorder.

"He's very manly, and he can be stubborn like Latino men can, but he's protective and he cares so much and loves so hard. I've been blessed enough to have him in my life, and not just as my man, but also my best friend," she explained.

"I've been my heaviest in my relationship with Wilmer and also been my thinnest. He's seen it all and loves me equally, and it gives me confidence to know that."

The split comes just days after the death of Demi's beloved 93-year-old great-grandmother. "Life is so short," she wrote on Twitter last Sunday (30May16). "Cherish every moment you have with your family and friends... I hate saying goodbye But at least I get to say it. RIP my beautiful angel.. Forever will never be the same without you."