Katy Perry needs a “liver transplant” after partying with Rihanna for her bachelorette bash. The “Teenage Dream” singer enjoyed a “risque” night with around 25 female friends in Las Vegas on Saturday night, including her pop star pal, ahead of her upcoming wedding ceremony. “Signing up for a liver transplant now,” she posted on her Twitter page.

According to OKmagazine.com, the group wore “typical risque bachelorette-themed party items” - with Katy wearing a hat and veil with the word “Bride” attached - as they enjoyed food and drinks at the Casino Tower and the Hard Rock Hotel and Casino. The women then jumped into a stretch limousine and were driven to the MGM Grand, where they watched a performance of Ka by Cirque du Soleil.

After posing with the show’s dramatically-dressed gymnasts, the group returned to Katy’s hotel suite where they continued the party in private. The 25-year-old beauty was even presented with an “erotic” cake to celebrate her last few weeks as a singleton.

Reminiscing back over the weekend, Katy wrote on Twitter “That’s what you get for waking up in…,” a lyric from her hit single “Waking Up in Vegas.”

It has been a hectic few days for Katy, after her fiance Russell was arrested at Los Angeles International airport on Friday after attacking a paparazzi photographer for allegedly trying to take an intimate photo of her. Russell was handed the misdemeanor charge of simple battery.

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