Demi Lovato is back, and this time she's angry

"What fascinates me," she said, "is metal."

She continued by namechecking hardcore bands Dimmu Borgir and Job For A Cowboy, whose songs were called things like Reduced to Mere Filth and Tormentor of Christian Souls.

Then, the 15-year-old had second thoughts.

"I think [Disney Channel president] Gary Marsh would kill me."

That irreverent candour has always been part of Lovato's appeal. from her days on kids' TV to her platinum-selling music career, via stints on the US X Factor and the sitcom Will & Grace. But she's never fulfilled the promise of a Demi Lovato metal album... until now. 

The singer's eighth album, Holy Fvck, is a sonic assault of razor blade guitars and throat-scorching vocals that strips away the radio-friendly veneer of her earlier material.

She signalled the stylistic shift earlier this year, with an Instagram post captioned: "A funeral for my pop music." In the accompanying photo, Lovato raised both middle fingers to the camera, while surrounded by her record label team.

"It wasn't an actual funeral," laughs the star, "but I was in a label meeting and we all happened be wearing black and I was like, 'This is perfect because I'm not playing pop music anymore. This is a rock album.'

"I definitely wanted to go harder with the sound."