Britney Spears' ex-husband is set to marry his long-term girlfriend this weekend.

The 'Till The World Ends' hitmaker's former spouse Kevin Federline, with whom she has two sons, Sean Preston, seven, and Jayden James, six, obtained his marriage licence with Victoria Prince in Las Vegas on Friday night (09.08.13), shortly after a surprise proposal.

A source told UsMagazine.com: ''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 also told People.com that the couple, whose daughter, Jordan Kay, is set to turn two next week, was granted a marriage licence at 8.42pm on Friday night.

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.

The former couple wed in a low-key ceremony in September 2004 and reached a divorce settlement in March 2007 but are still on good terms.

Kevin started dating Victoria, 30, in 2008 and previously hinted he wanted to marry her.

During an interview with Ryan Seacrest in 2010, he said: ''Would I get married again? Definitely.''

But he later insisted he was in no rush to tie the knot again, saying: ''I just want to be happy. Right now, I really am happy. Victoria's a great person. She's an incredible person.''

Britney, who was also previously married to her childhood friend, Jason Alexander, for 55 hours after they exchanged vows in Las Vegas in January 2004, ended her engagement with fiance Jason Trawick in January 2013 and is currently dating Dave Lucado.