Bill Cosby spoke to a group of students Friday at a Vancouver high school. (CBC)

It's not everyday you get a call asking if a show business legend can speak to your high school, but that's what happened at Vancouver Technical School.

Vice-principal Hank Lyth told CBC News he picked up the phone this week to hear from a representative of actor and comedian Bill Cosby.

"He said Mr. Cosby heard all about the school," Lyth said. "He's interested in coming, 'so we'd like to come. So, are you guys busy Friday afternoon?'"

Cosby, who was in Metro Vancouver to perform at a casino, has a PhD in education. He wanted to talk directly to the assembled students. It's something he likes to do when visiting cities, his representative said.

A chair was set up on a stage in the auditorium of the school on Vancouver's east side.

'I passed through puberty with flying colours'

The room was full of hundreds of teenagers who weren't even born when Cosby's television show went out of production in 1992 after an eight-year run, although it still airs in reruns.

He had the audience on his side within seconds of sitting down.

"Seventy-two years old I am, and I used to be 14. Really," he deadpanned.

"I passed through puberty, with flying colours. And I discovered - thank God for puberty — that I had a purpose in my life. And I went to every female that I knew and had treated badly before my puberty and apologized to them."

Cosby also reminisced about talking to his father about an adolescent relationship.

"I said, 'Dad, this girl said to me, 'Our relationship has to stay platonic.' What's that mean?' He said, 'That means you aren't going to get any.'"

A young fan complimented the senior comedian and earned a hug. (CBC)

After his 30-minute talk, Cosby took questions, and showed he was still moved by flattery.

One student told him he was a big fan of his show.

"I love you so much," the boy said. "I watch your show at seven to eight every morning."

Cosby called the boy up to the edge of the stage and gave him a hug.