Call her Mamma M.I.A.

The Grammy-and Oscar-nominated rapper has announced on her MySpace blog that she has given birth to a son.

The rapper writes that her baby is "healthy, fine, beautiful" and the most amazing thing on this planet. She jokes that the two are working together on a tour.

The father is her fiance, musician Benjamin Bronfman.

A representative says the couple have declined to release the baby's name.

The "Paper Planes" singer had a scene-stealing performance at the Grammys on Sunday.

She strutted on stage with her swollen belly during a performance with Kanye West, Jay-Z, T.I. and Lil Wayne.

The rapper says she started going into labour hours later.