US songstress Demi Lovato has defended comments she made about Justin Bieber.

Rumours spread earlier this week that The X Factor US mentor took aim at the Canadian superstar during an audition when she told a male contestant: "Well, finally someone can sing the song the way it was meant to be sung," after singing 'As Long as You Love Me.'

Lovato explained her comment to MTV News: "What they didn't put in the tabloids is that I actually turned around 'cause the audience was like, 'Oooh' and I was like 'Actually, guys, you took me the wrong way.'

She added: "I actually explained myself right then and there, but they didn't put that on [US website] TMZ."

Lovato also went on to explain that while she meant no harm with the comments, she'll think more about what she's saying in future.

She said: "It is annoying, but it is what it is. I have to be more careful with the way that I word things, but I was home schooled so my grammar's not the best."

Lovato took to Twitter when the reports surfaced, explaining: "Btw - no shade thrown at Justin. So many people audition with his songs.. Finally someone sang it the way it was meant to be sung. Meaning, finally someone sang it the way JUSTIN sang it (sic)."