The pressure to be funny must be huge when you're a comedy icon.

At least that might explain why, in a phone interview with Bill Cosby, the legendary performer is disarmingly straight-faced. For example, when quizzed about where he's calling from, his response is simply "Siberia."

When asked if he'd like to give readers a heads-up on what they can expect from his show, he says "No," then elaborates: "There are some very interesting tidbits and it's about my observations of what I see and how I feel about them. They usually turn around with people laughing, which is the intent."

The rest of the conversation -- to promote his back-to-back shows tomorrow night at the Jubilee Auditorium -- is equally terse until the topic changes to comics who feel they have to be vulgar to be funny.

The notoriously squeaky-clean 69-year-old says people who use dirty jokes are simply playing to an audience which has been created by movies, TV and the media.

"I don't know when the line was drawn and then erased. I assume it happened somewhere around the time when my show (The Cosby Show) was in prominence, when they started to bring in Bart Simpson and Rosanne Barr and advertising them as 'not The Cosby Show.' I think newspapers, especially in the sports pages, began to put words in that used to be naughty.

"I think television and news started to talk about and gossip about entertainers and showing them dressed in certain ways.

"Now everything has been shifted and moved so that our children may sit in a car while the radio's playing, or some music playing, and they may hear some profanity that, according to the family, is as permissible as saying pass the salt."

Cosby believes one of the reasons he been so successful throughout his 45-year career is because he knows how to make people laugh without getting dirty.

"People are coming to see me because they love my sense of humour and they know that I am going to deliver on it. There is no profanity and there is no attack dog mentality," he says.

"There is also a feeling that we are friends. We talk about some things that I have seen and how I am growing and people enjoy that. It's actually very, very, very wonderful."

Cosby is no stranger to Calgary. He remembers the high number of unfinished developments in the downtown core during the recession in the 1980s. And he has memories of touring the Saddledome and meeting the Flames.

"They took me through the locker room of the hockey team and I was really impressed. Then I was amazed when I saw this punching, speed bag. I thought, 'Wow -- they really practise punching and fighting?'"