Ashlee Simpson-Wentz celebrates her birthday with her sister Jessica and hubby Pete at the Wet Republic Pool in the MGM Hotel in Las Vegas, NV.

Ashlee Simpson, her husband Pete Wentz, friends and family including sister Jessica, party it up in their VIP poolside cabana at Wet Republic in Las Vegas, NV.

Ashlee Simpson sips Cristal Champagne poolside, to celebrate her birthday, at Wet Republic in Las Vegas, NV.

Ashlee Simpson gets a birthday kiss from husband Pete Wentz while celebrating at Wet Republic in Las Vegas, NV.

Big sis, Jessica Simpson sneaks in a few texts on her phone while partying at Wet Republic with her sister Ashlee on her birthday.