Movie mogul Steven Spielberg is set to become a grandfather again - his actress step-daughter Jessica Capshaw is pregnant with her third child.

The Grey's Anatomy star and her husband Christopher Gavigan will welcome their latest addition later this year.

Capshaw announced the news on her Twitter.com page with a post which read, "It is with profound happiness and sheer delight that @Christopher_Gav and I can say that another sweet Gavigan baby is on the way!"

The couple wed in 2004 and is already parents to Eva Augusta, one, and Luke Hudson, four.