Katy Perry, who turns 28 years old today, is famous for her strong voice and her bold fashion choices, and she featured both at a 30-minute America Forward free campaign concert for President Barack Obama in Las Vegas.

Perry wore a tight white latex dress that was inspired by a ballot, showing the names of Barack Obama, Joe Biden and Mitt Romney under the title "President of the United States," which was printed across her torso (Paul Ryan didn't make the cut — the dress was too short). On Perry's right hip, the checkbox beside Obama and Biden was filled in, leaving Romney's checkbox blank.

Perry sang opened with a cover of Al Green's "Let's Stay Together" before launching into her own hits, which included "Teenage Dream" and "Firework." She also encouraged the attendees — at least, those of voting age — to go out and check their own ballots a week from Tuesday, before introducing her grandmother, Nevadan Ann Hudson, 91, to the audience.

The President himself later praised Perry, reports the San Francisco Gate. "I am so grateful to Katy Perry for the unbelievable performance," he said. "Getting to know Katy, she’s just a wonderful young lady."

The endorsement was enough to send Perry a-twitter. "So tonight was a great night! The PRESIDENT gave grandma and I unforgettable shout outs & now I am officially 28! Best. Birthday. Ever," Perry tweeted.

Earlier in the day, Obama had been in Burbank, Calif., filming The Tonight Show With Jay Leno.

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