Los Angeles - Former Saturday Night Live comedian Hannibal Buress is now best known as an accuser of comic Bill Cosby.

Writer-actor Buress, 31, who has a role opposite Seth Rogen in the recent comedy Bad Neighbours, has scored an online success with his stand-up routine in which he calls Cosby, the iconic television father, a rapist.

Buress had performed the joke for six months before his performance in Cosby's hometown Philadelphia last month was filmed and published online by Philadelphia magazine.

In his joke, he explains why he hates Cosby's smug public persona as a big African-American television star, said TheWrap website.

He channels Cosby, saying: "Pull your pants up, black people. I was on TV in the 80s. I can talk down to you because I had a successful sitcom."

Then he adds: "Yeah, but you raped women, Bill Cosby. So, brings you down a couple notches. I don't curse on stage. But yeah, you're a rapist."

He also asks his audience to "Google 'Bill Cosby rape'", promising the search will get "more results than Hannibal Buress".

Days after the joke went viral, Buress said the attention was "unexpected". On radio's The Howard Stern Show, Buress called the charges against Cosby "information that's out there".

He added: "It wasn't my intention to make it part of a big discussion. It was just something I was doing at that venue, right there."

In a story in GQ magazine last year about the 30th anniversary of Cosby's stand-up concert movie Bill Cosby: Himself, Buress, Jerry Seinfeld and Sarah Silverman were among the comedians who paid homage to the star.

Buress said of Cosby's work: "It's stuff that holds up. All of it is evergreen."