Kate Hudson and Muse frontman Matt Bellamy welcome a baby boy on Saturday, whose name has yet to be announced.
The healthy newborn will join big brother Ryder, her son with ex-husband Chris Robinson, the lead singer of the Counting Crows.
Hudson and Robinson divorced in 2007. Kate and Bellamy were engaged in April, but have not yet announced a wedding date.
Kate did not let her pregnancy keep her from hitting the red carpet, and was out and about at premieres and events in the weeks leading up to delivery.