BUZZ: Mel Gibson's Girlfriend Gives Birth
11/01/2009 AT 04:00 PM EST
The baby, who was due in December, arrived Friday, says RadarOnline.com.
Gibson, 53, has seven children (six sons and a daughter) with his estranged wife Robyn, while Oksana has a son, Alexander, with her former boyfriend, actor Timothy Dalton.
"I have a 12 year old, so I've been a mother for 12 years – and of course, there is no first time mother's trepidation as such," Grigorieva, 39, said on a British TV show in September. "So naturally it's more relaxed, and I'm very dynamic so the pregnancy falls into my work schedule."
In terms of her relationship with the actor-filmmaker, she said, "Actually we have no plans to marry whatsoever. I haven't thought about it – we haven't spoken about it."
In April, the actor's wife of 30 years, Robyn, filed for divorce. Later that month, he and Grigeorieva made their first public appearance together as a couple.