Demi Lovato opens up about eating disorders, rehab and Joe Jonas

The 18-year-old has had a tough year after being admitted to rehab for 'emotional and physical issues.'

And now Demi has revealed the extent of the troubles which led to her seeking treatment last November. 

She told Ryan Seacrest on his KIIS FM radio show yesterday: 'I became like a little brat on set.

'I just had so much growing up to do, not that I ever intended to be that way. I just had so much going on in my head. It all just boiled up and I ended up doing things that I regret to this day.'

The Sonny With A Chance star ended up getting help after allegedly punching a back up dancer during the South American leg of the Jonas Brothers tour.

She said: 'It was the elephant in the room.

'Everyone knew about it. It was affecting every aspect of my life. I was cranky, I was irritable, I was not pleasant really to work with.'

Lovato then entered a treatment centre last November in Illinois.

She said: 'My family's known that I have had issues with food and eating for about six years now.

'I was able to check in with them but it got to a point where I just was lying to everyone about eating and about being happy.

'There is a lot of pressure these days. I feel like I live in a city where no woman eats.'

The star added she was 'never suicidal' during rehab, but said she was in 'some really really dark times.'

Ryan also asked Demi if her former boyfriend Joe Jonas knew about her problems while they filmed movie Camp Rock together.

She added: 'He was my best friend for years prior to that so he knew - when we shot the first movie together.

'Obviously I'm not super close with him any more just because a lot has happened, but I was very thankful to have the support of a lot of friends.'