nataliebabyboy.jpgIt's a baby boy for Natalie Portman and fiancé Benjamin Millepied!

The Oscar winner has welcomed a son, her rep tells PEOPLE, but all other details (including the name!) have yet to be released.

Portman and Millepied met on the set of Black Swan (he was a dance choreographer/costar) and they announced they were engaged, and expecting, last December.

When Natalie won her Best Actress Oscar this year for Black Swan, she thanked Millepied for giving her the "greatest role of all".

Congrats to the happy pair!