Demi Lovato is returning to The X Factor for a second season and – even though they publicly butted heads on the show last year – Simon Cowell said he “couldn’t be happier.”

But the sharp-tongued Brit couldn’t resist poking fun at the 20-year-old singer, saying she is “really, really annoying.”

“I couldn’t be happier that Demi wants to come back this year,” Simon said after Fox made the announcement Thursday.

“She’s a superstar in her own right and was a fantastic mentor last year.

“Even though she can be really, really annoying - I truly enjoyed working with her and so did the artists.”

Demi will be the only judge from last year, bar Simon, to return to the show - L.A. Reid and Britney Spears have since parted ways with the competition.

Demi gushed: “I am so excited to return as a judge and mentor on The X Factor.