Bristol Palin squared off in a heated argument with a bargoer at Saddle Ranch bar in West Hollywood Thursday after he called her mother, former Alaska governor, Sarah Palin, a whore.

Bristol, 20, had just fallen from a mechanical bull while filming her reality show for the BIO network when she was heckled by a 47-year-old man, CBS Los Angeles reported.

Did you ride Levi like that?, referring to Levi Johnston, the father of Bristol's young son. Your mother is a whore! he yelled at her. After being bucked off the bull, Bristol is shown walking over to confront the heckler.

The entire encounter was caught on tape by HOLLYWOOD.TV, and posted on YouTube Friday morning. The video obscenity-laced exchange (on the part of the heckler) shows the two talking for several minutes about why he doesn't like Sarah Palin.

Heckler: She's evil.

Bristol: Is it because you're a homosexual? And that's why you hate her?

Heckler: Pretty much. And why did you say I'm a homosexual?

Bristol: Because I can tell you are. That's your big boyfriend right there. She lies about what, sir? She lies about what, seriously? I'd love to hear. Can you give me one example, because you haven't yet?

Heckler: Everything about Obama. She lies.

Bristol: Really? Sir, sir listen. You haven't given me one example. So if you're going to call my mother a whore, I'd love to hear one example.

Refusing to back down, the verbal brawl ended when the heckler said, You don't look anything like Glen Rice, I thought you would, referring to the recent allegations that Sarah Palin had a one night stand with the former NBA player.

You're right, you're right, I'm half African American, you caught me, Bristol said, storming out of the bar with her TV show camera crew in tow. You're f---ing white trash from Wasilla. Your mother ran that city into the f---ing grave, the heckler screamed as she left.
On Saturday, Bristol's rep told TMZ: Bristol was approached in a confrontational and inappropriate manner when two men aggressively shouted expletives aimed at her in reference to her mother. Bristol responded to the unprovoked verbal assault by calmly standing her ground and defending her family.

A manager at the Saddle Ranch declined to comment.