The `Heroes` actress and husband Hayes McArthur welcomed their first child, a son named Theodore Hayes into the world on Monday (20.12.10), her spokesperson has confirmed.
The couple said in a statement to UsWeekly.com: "He`s our perfect Christmas present."
Though the pair never confirmed they knew the gender, pals confided recently that they had begun preparing for the arrival of a boy.
One source said at the time: "She is so excited about shopping for the new baby - she has been going overboard buying everything. Although she is only in the beginning stages of putting together the nursery, Ali definitely wants to keep everything eco-friendly and simple."
The 34-year-old star - who married Hayes, 33, in August 2009 after two years of dating - was said to be particularly enthusiastic about shopping in high street stores Target and Baby Gap.
The source said: "She couldn`t believe how much baby stuff they carried!"