Britney Spears' ex-husband married his long-term girlfriend on Saturday night.

The "Scream & Shout" hitmaker's former spouse Kevin Federline, with whom she has two sons, Sean Preston, seven, and Jayden James, six, tied the knot in a low-key ceremony, just one day after popping the question to Victoria Prince in Las Vegas on Friday night. Clark County Records granted the couple, who began dating in 2008 and whose daughter Jordan Kay is set to turn two next week, a marriage license shortly after they got engaged and a source confirmed to UsMagazine.com that Kevin is now married to the special education teacher.

"Kevin told her he was going to Vegas for a job, but he surprised her by proposing and [then plans on] marrying her while they are there. Victoria really wanted this for a long time so she's gotta be blown away. She's proven herself with him from day one. Victoria is an awesome girl," a source said.

Kevin, 35, began dating Britney, 31, in mid 2004 shortly after his split from long-term girlfriend Shar Jackson, while she was pregnant with their second child, after meeting the "Toxic" hitmaker on her world tour, for which he was a backup dancer. They married in September 2004 and reached a divorce settlement in March 2007 but are still on good terms.

Kevin previously hinted he wanted to marry Victoria but insisted he was in no rush, saying, "I just want to be happy. Right now, I really am happy. Victoria's a great person. She's an incredible person."