"Gimme More" isn't just the name of one of Britney Spears' hit singles—it's also what her ex, Kevin Federline, is demanding from the Princess of Pop.

The former backup dancer and “PopoZão” rapper is seeking an increase in child support payments following the smash success of Spears' Piece of Me Las Vegas residency, which earned $137 million across four years, Us Weekly reports.

Federline currently receives $20,000 per month in child support, but in a letter sent by Federline's lawyer to Spears' legal team, the pop star's ex has requested an increase in order to “recognize the sacrifices he has made because he has gone above and beyond what most people would do in this situation," a source told the tabloid.

"Kevin has always been supportive of Britney’s recovery and has always recognized what a great mother she has been,” the source continued, adding that Britney, who is under the conservatorship of her father, Jamie, likely "won’t be involved with any of the legal discussions regarding the increase request."

Spears and Federline, who were married between 2004 and 2007, share two sons together: Jayden, 11, and Sean Preston, 12. In 2008, Spears lost sole physical and legal custody of the boys.

Britney Spears Through the Years:

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