Cast member and singer Katy Perry performs at the premiere of "Katy Perry: Part of Me" in Hollywood
Cast member and singer Katy Perry performs at the premiere of "Katy Perry: Part of Me" in HollywoodReuters

The United States presidential election, 2012 campaign is getting hotter by the day with the voting day drawing near, and Katy Perry added spice to it as she performed at a Barack Obama campaign rally wearing a bizarre dress.

Katy Perry hit the stage on Thursday in a tight white dress with the words "PRESIDENT OF THE UNITED STATES" printed across her chest, below which the names of Obama, Vice President Joe Biden and Republican presidential candidate Mitt Romney were written. A black mark was written next to his name.

The 28-year-old singer belted out some of her hit songs including "Teenage Dream" and "Firework", and also Obama's favourite song, Al Green's "Let's Stay Together" before a huge crowd at a free concert in Las Vegas.

She had earlier this month sung at a fundraising event for the president.

Barack Obama has got a setback in the last week's public debate where his rival candidate Mitt Romney scored good points.

Obama talked about Katy's grandma in good humour during the rally.

"I've got to know Katy and she's a wonderful young lady. And I can tell that part of it is because of her outstanding grandma Anne, a 50-year resident of Nevada. The only thing I have to say is Anne got some lipstick on me when she kissed me. Fortunately somebody wiped it off before Michelle saw it," The Sun quoted Obama as saying to the crowd.

Katy Perry also celebrated her 28th birthday with the US First Lady Michelle Obama Thursday by having lunch together.

"So tonight was a great night! The PRESIDENT gave grandma and I unforgettable shout outs & now I am officially 28! Best. birthday. ever. (sic)" she tweeted.

"NOW my bday is complete! Lunch with @MichelleObama #chicvote (sic)" she added.