Grammy-nominated songwriter Kara DioGuardi, who has written hits for celebrities such as Gwen Stefani, Kylie Minogue and Christina Aguilera, will join American Idol’s eighth season, which is scheduled to begin in January on Fox.

Along with Simon Cowell, Randy Jackson and Paula Abdul, DioGuardi will decide who has the proper skills to become the country’s next superstar in the latest series of the reality-competition show.

"I'm going to be a straight-shooter," 37-year-old songwriter said. "I'm just somebody who's really honest and gives my opinion."

The changing of the trio into a quartet is part of a range of adjustments aimed "to keep the show fresh (and) make it a bit more unpredictable again," according to executive producer Cecile Frot-Coutaz.

This isn’t the first time the hit show’s producers have attempted to bring a fourth judge. Rapper and Radio personality Angie Martinez joined the second competition, whose winner was Ruben Studdard. But after three days the deejay left the show, saying she couldn't criticize singers who dreamed so much at their talent being appreciated.

During a conference call, DioGuardi said she'll be constructive with criticism, and not destructive. Also, she gave her word that she would be sincere and correct when evaluating the participants. "If I feel I need to be hard with someone to get that across, I will be. If I need to be softer or more nurturing with some of the contestants, I'll be that," she said.