The couple welcomed little girl Jordan Kay on Monday. This is the first child for Prince, 28.
In March the pair announced that they were expecting their first child together.
Federline and Prince, a former competitive volleyball player from Washington state, have been together for three years.
Federline has two children with former girlfriend Shar Jackson, son Kaleb, 7, and daughter Kori, 10. He also has two boys born from his marriage to Britney Spears: Jayden James, 4, and Sean Preston, 5.
In the spring, Spears and Federline were reunited to encourage their eldest son during his baseball game.