Iron Man star Robert made the announcement in his witty signature style via Twitter last night (9 July), revealing that his wife Susan is expecting a baby girl in November.
He said: "Yo. Susan. Me. Baby. Girl. November. Scorpio?"
Robert also wrote on his Facebook page: "Um. I don't know if it's a 'man's world', but I'm certain women run it. Susan and I are therefore delighted to announce we are expecting a baby. Girl. November. rdj."
This will be Robert and Susan's second child together. The couple, who have been married for nearly nine years, welcomed son Exton Elias in February 2012.
Yo. Susan. Me. Baby. Girl. November. Scorpio?— Robert Downey Jr (@RobertDowneyJr) July 9, 2014
Robert, who plays Tony Stark in the Iron Man franchise, is also father to 20-year-old son Indio from his previous marriage to actress Deborah Falconer.
Robert and film producer Susan met on the set of Gothika in 2003, and tied the knot in August 2005 in New York.
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