Bebe Rexha has attacked the trolls who poked fun at Demi Lovato's drug issues for revealing she was enjoying the 21 Savage backlash online.

The Cool For the Summer singer, who is battling sobriety following an overdose last summer (18), became a target of the troubled rapper's fans on Sunday (03Feb19), when she tweeted her favourite part of the Super Bowl were the 21 Savage memes that popped up online following news the rap star had been arrested by Immigration and Customs Enforcement officials for reportedly overstaying his visa.

The backlash prompted Demi to delete her Twitter account, stating: "If you’re gonna come at me for making a joke, try coming at me with some original not involving drugs (sic)."

And she had Bebe in her corner on Monday - the pop star tweeted: "To all the people who talked s**t to Demi you’re F**KIN DISGUSTING. Attacking someone that is 6 months sober about her personal issues with drugs and mental health over a tweet is LOW."

Rexha's comments come just weeks after Lovato had her back in an attack on designers.

Bebe took to Instagram and posted a video detailing her frustrations over not being able to nail down a designer for a Grammy Awards gown.

The singer insisted it was because top fashionistas thought she was "too big".

Demi saluted her for her stance, writing: "F**king preach! Love this and you for speaking your mind and using your voice!!!"

Lovato, who has battled eating disorders and self-hate problems in the past, has often spoken out about body image issues.

Her support for Rexha was one of Lovato's first social media posts since she checked out of rehab last summer (18).