Demi Lovato is proud to flash her underboob.

The 'Sorry Not Sorry' hitmaker appeared on Ellen Degeneres' YouTube show the 'Show Me More Show' and listed off a number of incidents that she will never apologise for and others she wish she could.

Demi revealed she wouldn't apologise for snoring on aeroplanes, going through an emo stage, showing skin, flashing underboob, regifitnig - and said she does it all the time - and even hooking up with an ex.

However, the 25-year-old star admitted she would apologise for getting embroiled in Twitter feuds, though she didn't name who with.

Demi recently created a documentary series 'Simply Complicated' which detailed her previous struggles with substance abuse and eating disorders, as well her current battle with bipolar disorder.

The 'Confident' singer entered rehab in 2010 to seek treatment for a dependence on alcohol and drugs, as well as get therapy for an eating disorder and self-harming, and although she's been clean ever since, she admits it's still a struggle to keep herself sober.

Speaking recently about her documentary series, she said: ''I think what was difficult about the process was being honest about where I am in my life today.

''Telling the world that I'm not the poster child for recovery.

''Sometimes it is a struggle, and sometimes I still deal with issues that I have suffered from in the past.

''It's a challenge to maintain recovery, and I talk about that in the film. So, for me, it's like kind of admitting that I'm not ... Obviously I'm not perfect, but admitting that on camera.

''I want to be the best role model that I can be for my fans, so by admitting that I'm not perfect, it's kind of weird for me.''