The 'X Factor' USA judge found it hard to forgive the Jonas Brothers singer - who she met on the set of 'Camp Rock' in 2007 - when he dumped her out of the blue in 2010, but the pair have since put their differences aside and become firm friends.
Speaking on ABC's 'Nightline News', Demi said: ''We were in a relationship and we broke up, and at one point, I was really mad at him.
''Now, I can, fortunately, say, that him and his brother Nick, have always been there for me, and are literally family, and like brothers.
''We have a great friendship. And we may not be as close as we used to be, but that's OK.''
Joe swiftly moved on to 'Twilight' star Ashley Greene after splitting from Demi just before the Disney stars were about to hit the road on their 'Camp Rock 2: The Final Jam' tour, and the 20-year-old singer confessed it wasn't easy getting over him.
She mused: ''When you go through heartbreaks and things like that, you always have in mind somebody. It's like when you hear a song on the radio that reminds you of somebody, you're going to be reminded.
''But keeping that in mind... it's a delicate balance.''
Demi - who spent time in rehab for an eating disorder, self-harm and emotional issues in late 2010 - believes all her struggles in life have made her a stronger person and got a new tattoo last week (15.05.13) to celebrate how far she's come.
The star had the words ''Now I'm a warrior'' inked on her left shoulder to mark the release of her fourth album, 'Demi'.