Kevin Federline is demanding an increase in child support from his ex, Britney Spears.

The "Toxic" hitmaker recently had a successful Las Vegas residency, with "Britney: Piece of Me" grossing over $137 million during its four-year run. Now that her residency is over, Federline is reportedly asking for an increase in child support.

Us Weekly reports Federline's lawyer Mark Vincent Kaplan has sent a letter to Spears and her team, detailing the reasons why his client deserves to get more than his current $20,000 monthly payment. "Kevin has always been supportive of Britney's recovery and has always recognized what a great mother she has been," an insider told the media outlet.

K-Fed's main reason for his request was to "recognize the sacrifices he has made because he has gone above and beyond what most people would do in this situation," added the source.

Spears, 36, was married to Federline, 39, from 2004 until 2007. They share two sons, 12-year-old Preston and 11-year-old Jayden. The "Piece of Me" singer lost sole physical and legal custody of their kids in 2008 after a highly publicized breakdown.

The former "Mickey Mouse Club" star is now in a relationship with personal trainer Sam Asghari, 23. She recently announced that she will be hitting the road soon for her "Britney: Piece of Me" tour. This will mark the pop superstar's first-ever tour in the United Kingdom in seven years. U.S. rapper Pitbull will serve as her support act for the series of shows.

Multiple reports claimed earlier this month that Spears thinks Asghari is "the one" for her. Although she was not really looking for a serious relationship when they met, the blonde beauty has fallen "head over heels" with the dancer and wants to build a family with him in the future.