The 'Pretty Woman' star - who has three-year-old twins Hazel and Phinnaeus and a five-month-old son Henry with husband Daniel Moder - was furious after spotting the paparazzo outside a Los Angeles school and decided to tail them when they drove off.
Julia, 40, then pulled up alongside them on the wrong side of the road angrily beeping her horn and forcing them to pull over.
The irate actress stormed up to the photographer's vehicle, and fumed: "So listen, you are going to turn your camera off and I am going to talk to you about how you were at a school where children are."
Julia is not the first celebrity to lose her cool with the paparazzi.
Earlier this month, George Clooney lost his temper with a photographer who was trying to get a picture of him and girlfriend Sarah Larson driving through Los Angeles on his motorbike.
George - who was involved in a motorcycle crash with Sarah in September - berated the man for "driving like a maniac".
He screamed: "How many laws did you just break? Do you know how many people you just put in danger?"
Julia showing a pic of her son Henry, born in June on Oprah recently.
Besides driving on the wrong side of the road, Julia parks in handicapped spots so she doesn't have to walk too far.
See also:
Julia Roberts Has a Look a Like - Wants to Help Britney
Julia Roberts is Still Pretty Woman
Julia Roberts is Granny Shopper
Filed under: Celebrity • Julia Roberts •
