AceShowbiz -

Rihanna once again becomes the subject of diss after KISS' Gene Simmons put the word out there that she is one of those "karaoke" singers. This time, a similar comment came from "American Idol" runner-up Clay Aiken who is currently one of the remaining contestants on "The Celebrity Apprentice".

Aiken made an appearance on Bravo's "Watch What Happens" in which host Andy Cohen asked which pop singer out there will not make it pass the first few rounds of "Idol". He said, "Oh God, there're too many. Too many...Current pop singer? I've stopped listening to them because they can't sing." He added, "Um...Rihanna has some pitch problems for sure. She does...Now I'm gonna get in trouble, too."

Aiken also made a startling confession during the interview, saying he had a plastic surgery that removed the fat in his chin recently. "I had surgery on my jaw for a TMJ thing and I had them suck the fat out of my chin while they were in there," he admitted. "I was like, you know what, while I'm already down, go ahead and take the vacuum in there and suck the fat out of my chin."