It's a Girl for Mark Wahlberg

By Sarah Michaud

Wednesday January 13, 2010 01:05 PM EST

It's a Girl for Mark Wahlberg | Mark Wahlberg

Mark Wahlberg and Rhea Durham

Jon Kopaloff/FilmMagic

Baby makes six for Mark Wahlberg and Rhea Durham, who welcomed a daughter on Monday, a source confirms to PEOPLE.

Grace Margaret Wahlberg joins siblings Brendan, 16 months, Michael, 3 ½, and Ella, 6.

The Lovely Bones actor, 38, confirmed the pregnancy in October, announcing that Durham was expecting a girl.

Will the brood continue to grow now that Grace has arrived? That's up to his model wife, Wahlberg says.

"My wife is allowed to pick the magic number ... as many as she wants to have."

• Reporting by JULIE JORDAN