Pitt, Jolie celebrate Maddox's birthday

Brad Pitt and Angelina Jolie have reportedly celebrated their oldest son Maddox's birthday.

According to Radar Online, the couple took Maddox, who turned nine earlier this week, Pax and sisters Zahara and Shiloh to the Go Kart World in Carson, California on Saturday.

A source said: "They stayed for about two hours. Brad and Angie were very nice people and only asked other people there not take pictures."

Liev Schreiber recently revealed that his and Jolie's children had playdates on the set of Salt.

Salt is currently playing in US cinemas and is released in the UK on August 20.