The 'Heart Attack' hitmaker admits she feels the need to outdo her fellow former Disney stars musically and realises that she needs to "focus" on herself and not let rivalry consume her.
She explained to MTV News: "I'm so excited for Selena, I'm so excited for Miley... I get competitive as much as I love them. I do get competitive so I have to focus on myself and just be like, 'It doesn't matter who has what.' We are all equally successful [in our careers] and in our lives. It's a huge blessing. I'm so proud of everyone."
The 'X Factor' USA judge previously said she felt "protective" of Miley, 20, and has warned the 'We Can't Stop' singer about her party-loving ways.
She said: "She knows how I feel about the whole partying thing. I love her to death and I'm always like, 'Just be careful,' and she's like, 'Dude, I'm chilling. It's fine.' But I care for her so much that I'm so protective, but she's good. She's got a good head on her shoulders."
Despite her competitive nature, Demi, 20, also admits she loves Miley's song new song.
She added: "I think it's ['We Can't Stop'] great. I think it's a good song ... it's a song a lot of people have fun to and if people are enjoying it, then great."