“Platinum Hit” judge Kara DioGuardi — who spent two seasons judging on “American Idol” — says she’s psyched about her upcoming Broadway debut.

“I’m going to be in ‘Chicago’ on Broadway in September,” she says. “I’m going to be Roxie, taking over the role Christie Brinkley was in. It’s my Broadway debut, and I have ‘Idol’ to thank for all the great things I’m getting to do. It’s opened up a whole new world for me, and I’m much more confident than I was before.”

That’s apparent in DioGuardi’s mien on “Platinum Hit,” Bravo’s songwriting series airing its fourth episode tonight at 10. DioGuardi judges on the show along with Jewel (who also hosts).

I asked DioGuardi if there’s anything that surprised her about “Platinum Hit” (the first season finished taping and is in the can).

“There’s a lot of drama . . . I’m not surprised, but I enjoy watching the episodes because I didn’t see the drama behind-the-scenes,” she says. “I knew there was a bit of romancebetween Johnny [Marnell] and Jes [Hudak] . . . and when they cut to the other contestants, they’re all throwing each other under the bus.

“It’s entertaining, but at the same time, I thought these were nice girls and nice guys.”

She also says she thinks there’s a “learning curve” underway for the show’s viewers.

“This is about your song, not your voice, and someone might not have a great presentation or voice — but we’re listening to the melody and the lyrics,” she says.

“Hopefully the audience will get their heads around that and see what we’re looking for.”

Last week, DioGuardi was at the “Good Morning America” studio in Times Square for the crowning of the 2011 Folgers Jingle Contest winner. For the second consecutive year, Kara helped judge the contest, which awarded this year’s winner, Courtney R. from Gloucester, Mass., with $25,000, a music mentoring session and the chance to appear in an upcoming Folgers commercial.

“She’s a singer/songwriter who had an interesting take on [the jingle] — she almost had a Diana Krall-type feel in her voice and she had a great stage presence,” DioGuardi says. “I thought contestants were a cut-above last year and we had so many genres represented — R&B, jazz, singer/songwriters. They were really good, I have to say.”

Last, but not least:

*Tony Dovolani, Matt Lauer, Chris Wragge, Harry Smith, Richard Kind and Alan Kalter are expected at today’s Autism Speaks Thirteenth Annual New York Celebrity Golf Challenge at the Winged Foot Golf Club in Mamaroneck . . . I pulled a wrongo: the Ford Mustang Boss event at the W Hollywood, hosted by Topher Grace, was sponsored by Ford Mustang Boss.

Contact The Starr Report: mstarr@nypost.com.