BEVERLY HILLS, Calif. (AP) -- Simon Cowell says Britney Spears and Demi Lovato are the tough cookies on "The X Factor."

With the new "X Factor" judges at his side Monday, the reliably acerbic Cowell said Spears is "quite mean" and Lovato is "a brat." But, Cowell added, he's long wanted to work with Spears and said "there's really something likable" about Lovato.

The pop stars are joining his "X Factor" for its second season.

Spears and Lovato replace judges Paula Abdul and Nicole Scherzinger, who left after the show's debut year fell short of the spectacular ratings Cowell predicted. Antonio "L.A." Reid and Cowell will return as judges.

The "X Factor" panel spoke to a Beverly Hills, Calif., meeting of the Television Critics Association by satellite from Miami.