LOS ANGELES - Kara DioGuardi was fretting about being the new face of "American Idol," and she put the blame on hungry mosquitoes.

"Here I am in Hawaii and I wake up yesterday and I'm covered in mosquito bites, 15 to 20, and it looks like I have the chicken pox," the songwriter-producer said on Tuesday.

"Nobody cares about a songwriter with mosquito bites. But a judge on `Idol' who's about to go in front of the press, that's a whole other story," said DioGuardi, who has joined the "American Idol" judging panel and has a whirlwind promotional schedule next week in New York that includes David Letterman's show.

DioGuardi is a hit machine whose songs have been recorded by Gwen Stefani, Faith Hill, Marc Anthony and others, including past "Idol" winners. She represents a big change for the hit Fox series, which is adding a new voice to those of veteran judges Simon Cowell, Randy Jackson and Paula Abdul in an eighth-season effort to freshen its familiar formula.

"American Idol" was the No. 1 program last season despite a small ratings dip, and DioGuardi said she's honored to be part of it. The season debut, and hers, is Jan. 13 (8-10 p.m. EST).