Christina Aguilera had better get her lullaby repertoire ready.

The Grammy winner and fiancé Matt Rutler welcomed a baby girl, their first child together, on Saturday. Aguilera, 33, gave birth via a C-section at Los Angeles' Cedars-Sinai Medical Center, according to Us Weekly.

The songstress is already mom to a son, 6-year-old Max, with ex-husband Jordan Bratman.

Aguilera and Rutler, who met on the set of the 2010 flick "Burlesque," announced their engagement this past Valentine's Day.

"So blissful in taking this time for creating all things blossoming new on the horizon...album, baby & beautiful music to come," Aguilera shared via Instagram in April, along with a photo of herself and Rutler, a production assistant, smiling.