The musicians "are expecting a baby and are engaged to be married in a private ceremony later this year," reps for the couple said. "They're very happy."
The announcement comes after the two, who have been together since fall 2008, attended a Black Ball in London for Keys' "Keep a Child Alive" charity on Thursday, May 27.
Swizz Beatz (Kasseem Dean) has two sons, Prince Nasir, 9, and Kasseem Jr., 3 , both from previous relationships. This will be Keys' first marriage and the couples' first child together.
Alicia Keys, Swizz Beatz and Jay-Z Live at Madison Square Garden