Credit: Flynet

They grow up so fast!

Natalie Portman gave a rare glimpse of her adorable 4-month-old son Aleph while leaving a friend's house in L.A. Thursday. The actress has kept a low-profile since giving birth to her first child with fiance Benjamin Millepied in June, spending most of her time in France and New York City.

Portman, 30, and Millepied, 33, first met on the set of 2010's Black Swan. Millepied served as the film's choreographer and appeared briefly on film, while Portman's chilling performance earned her the Academy Award for Best Actress. See more pictures of Aleph.

Baby Aleph takes his name from the first letter of the Hebrew alphabet; the name also represents the "oneness of God" and the element of air.