AceShowbiz -

Britney Spears' ex-husband, Kevin Federline, has made another attempt at getting more child support. The former dancer reportedly approaches Britney's father Jamie Spears for more money after seeing the success of her recent Las Vegas residency.

Kevin receives $20,000 per month to take care of their sons, and according to TMZ, he claims that it isn't enough anymore. Sources close to Britney tell the webloid Jamie is suspicious of Kevin and asks him how he's spending the money, but the latter refuses to answer.

The sources add that Jamie got a letter from Kevin's lawyer last week, asking for a chance to talk about the child support increase. And when they finally met, Jamie asked what the kids needed that Kevin could not provide, but Kevin's lawyer did not reply.

His lawyer was said to bring up Britney's recent residency success, saying that she was making a lot more money than him. But Jamie insisted that the extra cash didn't mean that Britney would provide their sons with an opulent lifestyle that Kevin could not afford.

A second insider tells Us Weekly that Kevin is currently preparing to take the matter to court. "Kevin truly wanted to try and settle the child support payment increase without getting the courts involved out of respect for Britney, and of course, their two sons," the insider says, adding that this likely won't be "resolved without a court intervention."

Meanwhile, another source close to Britney reveals that the issue causes the 36-year-old pop star "a tremendous amount of stress [because] Kevin does indeed have full physical and legal custody of the boys. She just wants this resolved as quickly as possible."

Britney and Kevin tied the knot in 2004 and divorced in 2007. They share two sons together, 12-year-old Preston and 11-year-old Jayden. The "Toxic" singer lost sole physical and legal custody of the boys in 2008.