Demi Lovato and Britney Spears have officially signed on to join the "X Factor" as judges this season.
Britney Spears just began her two-year residency at Planet Hollywood Resort and Casino in Las Vegas.

Demi Lovato and Britney Spears have officially signed on to join the X Factor as judges this season. While Simon Cowell, the show's creator, is confident about Lovato and Spears' judging ability, there is one person who does not have much faith in Britney Spears - Howard Stern. Stern is the new judge on Americas Got Talent.

I think it's a wonderful decision; Britney still thinks the world is flat, Stern said. We're going to tune in to see if she can sort of function through the thing. As far as any real criticism, I think Simon and L.A. Reid will be doing that. I think Britney's going to stand there and eat a lollipop and wear a sexy outfit; I don't anticipate great opinions from her. I think she's going to sit there like J.Lo. 'Oh, you're wonderful, you're terrific. You think I could get a perfume endorsement out of this? You think I can perform on the show?'

I think that's what it's about, but I think it will be interesting, Stern continued. I'll tune in to see what kind of train wreck she is, absolutely.

After judges Nicole Scherzinger and Paula Abdul were let go in January, there were many rumors about who would replace them. Big names like Beyonce, Mariah Carey, Janet Jackson, Fergie, Avril Lavigne, Miley Cyrus and more were thrown into the mix. Chatter became louder this year surrounding Lovato and Spears -- and now TMZ is reporting that everything is official for the two pop stars.

Lovato is expected to join Spears, Simon Cowell and L.A. Reid in New York City today for an official announcement about the new judges. On Monday morning, Spears was spotted going into the Mandarin Oriental Hotel in New York City's Columbus Circle neighborhood.

Spears was being courted by Cowell for several months before signing on. The pop star will reportedly receive $15 million for one season of work. Lovato's salary has not been announced and Fox has not commented yet on how much Lovato will receive.