From WENN.com

The former Buffy the Vampire Slayer star gave birth to a baby boy in Los Angeles in the last week (ends23Sep12). The new arrival is a little brother for the couple's three-year-old daughter Charlotte.

The actress' representative tells Us Weekly, ""Mother and baby are doing great. And Charlotte is very excited to be a big sister.""

The baby's arrival came in a very special month for Gellar and Prinze, Jr. - they celebrated their 10th wedding anniversary on 1 September (12), and Charlotte turned three last Wednesday (19Sep12).