The `Clueless` actress - who announced she was pregnant with her first child with her husband, musician Christopher Jarecki, in January - had a water birth at a Los Angeles birthing centre on 06.05.11, according to X17online.com.
Although Alicia has not announced the gender of the tot, mother and baby are both doing well and have already left the medical facility and returned home where the star celebrated her first Mother`s Day.
Before getting pregnant, Alicia made no secret of her desire to have a baby, and admitted wearing a pregnancy fat suit for her part in the critically acclaimed Broadway play `Time Stands Still` made her even more broody.
She previously said: "Wearing a pregnancy suit was so much fun. I loved the feeling of pretending to be pregnant and having little arms and legs and this big belly.
"I`ve been wanting to have a baby since I was two years old - I`m destined to be a mother."
Alicia, 34, and Chris, 40, wed in June 2005 on the shores of Lake Tahoe, California, after dating for eight years.