PalmsPool%20Diddy1%20090411%5B2%5D460.jpgChrstina%20Millian460Denise Truscello

Rap superstar Diddy and sexy R&B diva Christina Milian know how to have sexy fun in the summertime!

Diddy, 41, hosted a wet and wild party at the Palms Pool & Bungalows at the Palms Casino Resort in Las Vegas. We're told the rap mogul grabbed the mic and got the crowd going nuts with a performance of “Mo Money Mo Problems."

Milian, 29, left baby Violet at home for some quality adult time. Looking good, Christina!