Michael Richards, the actor best known as Kramer from "Seinfeld," apologized on Monday for a racially charged tirade at a Los Angeles comedy club.

"For me to be at a comedy club and flip out and say this crap, I'm deeply, deeply sorry," he said during a taping of David Letterman's "Late Show."

"I'm not a racist. That's what's so insane about this."

The 57-year-old actor appeared via satellite during an interview with comedian Jerry Seinfeld.

Richards lost his cool after repeated heckling from two black audience members during a stand-up routine at West Hollywood's Laugh Factory. A video of his rant was later posted on the showbiz website TMZ.com.

Michael Rechtshaffen, of The Hollywood Reporter, said the video may take away from Richards' efforts to apologize.

"We'll see what happens. Because in this day and age of YouTube and video phones, everyone is now accountable for their actions," Rechtshaffen told CTV Newsnet.

"If this was just something that happened in the comedy club, it might have swept under the rug, but now everybody knows about it."

Harvey Levin, who runs TMZ.com, said the heckling was not severe and should not have prompted such a fierce tirade from the comedian.

"It was simply a heckler who said, 'You know what? My friends don't think you're that funny.' That's all he said," said Levin.

"(The heckling) wasn't really horrible or over the line, and it just sent (Richards) off in to this incredible, racist tirade," Levin added.

Richards, best known for his eccentric role as Kramer on the hit sitcom "Seinfeld," was performing at the Laugh Factory in West Hollywood Friday night when he started spewing the racial slurs.

After the initial heckling, Richards retorted: "Shut up! Fifty years ago we'd have you upside down with a f------ fork up your a--."

But Richards' outburst didn't end there.

He then began pacing up and down the stage, yelling at the men for interrupting his routine in an expletive-laden tirade.

"You can talk, you can talk, you're brave now mother------. Throw his a-- out. He's a n-----!" Richards shouts before repeating the slur over and over again.

He also demanded one of the patrons be removed from the comedy club.

"He's a hugely popular guy as the character Kramer, but there was a clear dark side that emerged here at the Laugh Factory," said Levin.

Before his interview on the "Late Show," Seinfeld had said Richards was likely very upset over the incident.

"I'm sure Michael is also sick over this horrible, horrible mistake. It is so extremely offensive. I feel terrible for all the people who have been hurt," he said in a statement Monday.

While there is some audible chuckling in the audience throughout the outburst, someone can be heard gasping "Oh my God" while others are heard to say "Ooh" after Richard uses the n-word.

One of the men who was the object of the outburst shouted back that "That's un-f***ing called for, ain't necessary."

Richards eventually cut his act short and walked off the stage without any explanation.

The tape also shows audience members beginning to leave the comedy hall.

Richards performed the next night at the same comedy club without incident. The club's representatives said they wanted to give Richards a chance to express his regret over the incident, although he apparently never addressed the issue.

Fellow comedian Paul Rodriguez, who was also on the bill Friday night, said Richards had some explaining to do.

"Once the word n----- comes out of your mouth, and you don't happen to be African-American then you have a whole lot of explaining," he told CNN.

While comedians often cross the lines of good taste within their acts, Rodriguez said Richards' remarks far surpassed the boundaries of what is acceptable.

"Freedom of speech has limitations and I think Michael Richards found those limitations," Rodriguez told the network.