Pop sensation and 'X Factor USA' beauty Demi Lovato has revealed that she isn't bothered by potentially irritating her colleague and boss Simon Cowell because it's fun to wind him up.

When asked recently if he was angry at her for sharing old snapshots of him via her official Twitter page, which has 18.5 million followers, Lovato joked that he should expect a little mischief because she's young and likes to mess around:

"I don't really know for sure and I don't really care if he does because I'm going to do it anyway and that's what he gets for hiring a - at the time a 19 year-old - to be alongside him on the judges table."

After the 'Heart Attack' beauty uploaded the entertaining images back in June, Cowell responded by publicly tweeting a message to her that read: " "Demi. Stopppppppppppppppppp please with the horrific pictures. They are giving me nightmares."

She also recently confessed her admiration for Cowell's ability to be brutally honest and praised his bluntness: "Whatever he has to say, it's the honest truth. Sometimes I don't agree with him, but most of the time he says what I'm wanting to say but, like, I just physically can't because it's so mean! He knows what he's talking about, he knows what he's doing and he's gonna tell you straight up, whether you want to hear it or not."