Jennifer Lopez and Marc Anthony have renewed their wedding vows in a secret Las Vegas ceremony - four years after they first walked down the aisle.

According to People.com, the couple held their new nuptials at Caesars Palace's Forum Tower Penthouse at 3:15 a.m. (Gmt) Sunday, with two pals acting as witnesses.

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

The couple welcomed their first children together, twins Max and Emme, in February.