Jennifer Lopez and Marc Anthony have said "I do" again.

According to People magazine, the couple, who married four years ago, renewed their vows in Las Vegas on Sunday.

"It was totally a spur of the moment thing," a source told People. "They decided around 12:30 in the morning that they wanted to do it and started calling for ministers."

The renewal was witnessed by two friends at Caesars Palace's Forum Tower about 3:15 a.m. Sunday, People reported.

Renewing their vows at the same time were New York Mets outfielder Carlos Beltran and his wife, Jessica, the magazine said.

Lopez and Anthony married on June 5, 2004. The couple had twins, Emme and Max, in February.