AceShowbiz - Ashlee Simpson and husband Evan Ross' weekend took a disaster turn. According to a new report, the "Pieces of Me" singer lost her five-carat wedding ring while attending an after-party for the Pegasus World Cup at Gulfstream racetrack in Hollywood, Florida this weekend.

A source revealed to Page Six that the couple was partying at the trackside Carousel Club. Meanwhile, DJ Cassidy was doing a live version of his Internet-famous "Pass the Mic" set.

"They were [dancing] in the VIP area in front of the stage with Nicole Scherzinger and DJ D-Nice… when Ashlee started yelling 'My ring! It just flung off!' " the source shared. "She was very upset and nearly in tears. Her group of friends started searching around the area with Evan's iPhone flashlight."

It was also said that Evan even had to "lift up the sofas and chairs, looking underneath."

Thankfully, Evan managed find the platinum and gold stunner, which estimated to be worth around $500,000. "After almost an hour of searching, Evan looked in the bushes and found the ring in the dirt," the informant continued. After he picked it up, "he spun around and got down on one knee in front of Ashlee as if proposing."

Also attending the star-studded Pegasus World Cup was Nicole Scherzinger. She oozed glamour in a chic cream trouser suit with an oversized blazer and flared trousers. Meanwhile, Ashlee donned a brown blazer over a red-and-black patchwork sweater with her husband looking dapper in an all-white outfit with a bit of gold and pink trim.

As for the race, Life Is Good won the $3 million prize. During the "Pass the Mic" set, Ja Rule, Lil' Kim, Mase, El DeBarge and Jadakiss hit the stage.