Katy Perry was a headliner at a rally in Las Vegas for President Obama, but her parents couldn’t have been happy about it. They are fundamentalists, and hard right politically, who think Obama is the Great Satan.

But Katy, 28, has a mind of her own when it comes to politics and has been an avid supporter of the President’s.

To show that support, she wore a skin-tight latex dress during the show that was a facsimile of an election ballot. A big box was blacked in for the Obama, Joe Biden ticket.

Perry provided a glimpse into her background in her autobiographical movie “Part of Me.” Perry’s parents are Pentecostals, who believe in a living god, spirits, speaking in tongues, faith healing, the imminent return of Jesus, and, of course, the devil.

“We weren’t allowed to eat Lucky Charms [cereal] because luck is of Lucifer,” says Katy’s brother David Hudson.

“I couldn’t watch the Smurfs growing up,” Katy adds in the movie.

Perry took a break from performing to urge the 13,000 fans in the audience to register to vote. “Don’t wait. Go tomorrow. How many of you are 18 here? It’s going to be your first time, right?”

Obama flew out for the concert and joined Perry, who was there with her grandmother, on stage after her performance. “I’ve got to know Katy and she’s a wonderful young lady,” he said. “And I can tell that part of it is because of her outstanding grandma Anne, 91, a 50-year resident of Nevada.”

Obama is barnstorming swing states to shore up support for his re-election. He won Nevada in 2008 and has a slim lead there this time around.