Selena Gomez doesn't think she was ''fair'' to Demi Lovato.

The 21-year-old star drifted apart from her childhood friend when the 'Skyscraper' hitmaker checked into rehab for help with an eating disorder and self-harm in 2010, and Selena admits she backed away from her pal because she didn't ''understand'' what she was going through.

She said: ''I've known her since we were seven, and we did fall apart for a while.

''She was going through things and I was so young and it was confusing. I processed it saying, 'OK, I don't understand what she's going through so I'm just going to do this.' I don't think it was fair, and I'm so happy that I have her back in my life now.''

The 'Come & Get It' hitmaker - who has an on/off relationship with Justin Bieber - thinks the way her friend has got her life back on track is ''incredible'' and she says the former 'X Factor' judge is one of her biggest inspirations.

She told Seventeen magazine: ''I feel like we're all given what we can handle, and clearly someone thought she could handle so much - and she could, and she did. And she's incredible for that. I couldn't imagine going through some of the things that she went through, and the fact that she is who she is today is insane - she's one of my inspirations.''

These days, the former Disney stars are closer than ever.

Selena said: ''Demi's very, very strong. She's the only person that I would tell the deepest, darkest secrets to. The only person.''