[article id="1631618"]"American Idol" Hollywood Week[/article] kicked off on Tuesday night (February 9) with a slew of new faces up on the stage and one new face behind the judges' table. Some singers soared (like Andrew Garcia with his soulful take on Paula Abdul's "Straight Up"), while others crashed and burned (like Vanessa Wolfe and her shaky version of Blind Melon's "No Rain"). Almost everyone could agree, though, that new judge Ellen DeGeneres rocked out on her "Idol" debut.

Count Kara DioGuardi as one of the enthusiastic supporters. "When I was sitting next to her, I felt she had a really good handle on whether a contestant had a potential, whether they had star quality," she said of Ellen during a conference call with reporters. "She knew if something was off in the vocals or in the performance. I thought she delivered the message with kindness, but also had criticism in there."

DioGuardi was also quick to dismiss rumors of any on-set tension between Ellen and fellow judge Simon Cowell. "I think you have to take any rumor you hear about 'American Idol' with a grain of salt -- they're usually not true," she said. "Last year it was Kara and Paula [Abdul] fighting, hating each other, Kara sits in the corner. These things are just ridiculous. We're all there to do one thing and that's to find the greatest contestant, the greatest 'American Idol' winner we can find."

The Ellen/Simon contretemps wasn't the only rumor DioGuardi responded to during the call. She also took a whack at reports that Howard Stern might be replacing Cowell at the judges' table when he leaves the show at the end of the current season. "I don't think he has musical background or any kind of music anything," she said of Stern, clearly unhappy with the possibility. "If you're going to replace Simon, you have to have that background, you have to be somebody who knows about signing great artists and being a part of their career from the very beginning to the very end.

And then there's perhaps the most talked about element of Tuesday night's show: the new VitaminWater cups that replaced the long-established Coke cups on the judges' table. What's going on? Before being sure to point out that Coca-Cola owns VitaminWater, Kara gave the new cups a sort of Hollywood Week golden ticket.

"They were kind of colorful, different," she laughed. "Everything's always changing on the show. I kind of just drink from the cup and assume there isn't poison in it."

Get your "Idol" fix on MTV News' [article id="1486475"]"American Idol" page[/article], where you'll find all the latest news, interviews and opinions.