When Julia Roberts wants a little face time with you, it's probably best to comply, especially if she's feverishly honking at you to pull over. The Oscar-winning mother of three went into Mama Bear mode Wednesday in Los Angeles during a street-side confrontation with a paparazzo who was purportedly trying to nab pictures of her kids.

In video obtained by TMZ.com, Julia's Mercedes SUV can be seen giving chase to the snapper, pulling alongside him and repeatedly beeping to get him to stop.

Video: Watch angry Julia confront a paparazzo

With a swear and an audibly heavy sigh, the photog complies, but not before checking to make sure his camera is ready to capture the moment. The A-lister soon appears at his window.

"Hi, how are you?" Roberts asks the shutterbug, who, sensing he's in trouble, offers a sheepish, "Hi Julia. I'm so-..."

Before he can finish his seemingly apologetic sentiment, she launches into a lecture using her best stern mommy voice.

"Listen, you can turn your video camera off because I'm gonna talk to you about the fact that you're at a school where children go," reprimands Roberts. "Turn it off."

The shutterbug, in an act of self-preservation, turns it off.

Julia discussed her limited patience with the paparazzi at length during her recent cover story with Vanity Fair.

"I just feel like it's so demeaning the way they behave, and I hate the fact that I even put any of my energy into thinking about it or being stressed about it," she kvetched. "And really, more than anything, it just has to do with my kids."

According to Roberts, "There's no reason to take pictures of celebrities' children other than for people to say, 'Oh, they're cute.' I think magazines shouldn't run pictures of people's kids. I have a problem with that ... I get pissed off, because I think that it's inhuman to chase a woman with her children."

(Last week, she showed off a snapshot of 5-month-old son Henry while promoting "Charlie Wilson's War" on pal Oprah Winfrey's show, although that was likely her way of trying to diminish demand for his photo.)

Still, even when the megastar is sans Henry and 3-year-old twins Hazel and Phinnaeus, photographers are never far away. On Nov. 17, Julia and husband Danny Moder were snapped parked in a handicapped spot in front of a Malibu, Calif., supermarket (according to Us, she didn't notice the disabled signage until they were driving away).

Roberts' lensman tête-à-tête comes on the heels of George Clooney's serious but civil exchange last week with a still-rolling cameraman, who was said to be aggressively trailing him as he enjoyed a motorcycle ride with girlfriend Sarah Larson (now recovered from the foot injury she suffered during their September accident in New Jersey).

"How many laws did you just break?" asked the two-time Sexiest Man Alive. "You can drive all you want, you can take my picture all you want, but what you cannot do is put people in danger."

Clooney later fumed to "Entertainment Tonight," "They're not trying to catch me doing something stupid, they're trying to create me doing something stupid ... I don't want to restrict anyone's rights. Take your pictures but don't go 60 [mph] down a one-way street."

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