It's final! Britney Spears and her lawyers have crossed the t's and dotted the i's on their custody settlement agreement with Kevin Federline and his legal team -- and ET has the papers HERE!

The settlement has been finalized, according to The Associated Press, and in papers filed in L.A. Superior Court that were obtained by ET, Britney must pay her ex-hubby's lawyers, Kaplan & Simon, a final sum of $250,000 to cover their legal fees, while her monthly child support of $15,000 has been upped to $20,000 per month, beginning July 15.

Kevin has sole custody of their two little boys, Jayden James and Sean Preston, and Britney retains visitation rights.