"That's what you get for waking up in Vegas!"

We wonder if Katy Perry knew she'd be having her bachelorette party in Sin City when she wrote that song. The 25-year-old singer, who is getting ready to marry Russell Brand, invaded Las Vegas over the weekend with an entourage of 25 ladies, including Rihanna, to help her party her single days away.

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Their first stop was the massive pools at Hard Rock Hotel's Beach Club, where the girls drank and ate in a VIP cabana. The bride-to-be donned a white bikini with a veil attached to her bottoms, while Rihanna chose a hot, gold one-piece and silver cross necklace.

After a day in the sun, the girls got ready for the night's festivities, which included catching the Cirque Du Soleil show, Ka, at MGM Grand before heading to dinner at Ago. Then, it was time for some good ol' dancing at the hot nightclub, XS, where Katy and Rihanna sipped Grey Goose before heading to Sapphire strip club, where Katy got the true bachelorette treatment with a lap dance from a blonde!

She probably woke up in Vegas with one mighty hangover! (People)

Faye Brennan is assistant editor at BettyConfidential.

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