Jennifer Garner and husband Ben Affleck have welcomed a son.

A source close to the Hollywood couple told People magazine that the actress gave birth to their third child in Santa Monica.

The couple, who have been married for seven years, announced that they were expecting for the third time in August 2011.

The new arrival will join big sisters Violet, six, and two-year-old Seraphina.

The proud parents, both 39, remained tight-lipped about the sex of their baby throughout the pregnancy.

Last year, Garner told chat show host Ellen DeGeneres: "It would be so weird to have a boy." It would be "cool and different", she added.

No other details about the birth have been released and the family have not made an official statement.