Demi Lovato loves being a judge on The X Factor US because she gets to "mess with" Simon Cowell.

The 20-year-old singer discussed her role on the singing contest, where she is a panellist alongside Simon, Britney Spears and L.A. Reid. She enjoys finding new talent and mentoring the artists, but there is another aspect of the role which is also appealing.

"I get the privilege of being paid to mess with my boss all day," Demi laughed to talk show host Jimmy Kimmel.

Viewers in America recently saw Demi sit next to Simon on the panel, in the chair previously held by Britney. Producers requested she move because of her disagreements with music mogul Simon.

"We were just playing musical chairs," Demi explained. "They hated me [leaning] over to shout at Simon so they were like, we'll just put you next to him."

Although she gets on well with Simon, she would never date the 53-year-old because of his questionable style choices.

"He shows more cleavage than I do..." Demi teased. "[Would I date him if I was 25?] No! He parts his hair down the middle."