In this image released by Dos Equis via Rogers & Cowan PR, actress Carmen Electra and her fiance, musician Rob Patterson pose together at the Dos Equis party In Austin, Texas on Thursday, April 24, 2008. [Agencies]

Carmen Electra showed off her fiance and black diamond engagement ring, while the Hilton sisters frolicked with their beaus at an exclusive Coachella afterparty.

Paris Hilton and and Benji Madden arrived just before midnight, greeting DJ Steve Aoki with hugs at an airport hanger transformed into a makeshift nightclub about eight miles from the Coachella Valley Music and Arts Festival on Saturday.

While Nicky Hilton and David Katzenberg held court in a corner booth at the invite-only T-Mobile Tone Def After Party, Electra and Rob Peterson wandered with their hands firmly clasped together.

Electra announced her engagement to the musician on Thursday.

Paris Hilton and Madden were inseparable throughout the evening as they snapped photos of each other and friends, watched partygoers perform karaoke in the PlayStation 3 "SingStar" Lounge and scarfed down nachos and hot dogs from food trucks parked inside the event.

During the celebration, attendees were invited to customize T-Mobile devices and Michael Stars T-shirts, receive makeup makeovers from Too Faced Cosmetics, lounge on beds underneath vintage posters and dance to tunes provided by Aoki, Adam "DJ AM" Goldstein and "That '70s Show" actor Danny "DJ MomJeans" Masterson, who all operated from separate booths on the dance floor.