TORONTO -- Growing up on the TV and film sets of his late puppeteer dad, Brian Henson got to see the naughtier sides of Miss Piggy, Kermit and their fuzzy friends when cameras weren't rolling.

"The puppeteers would stay in character and they would ad-lib, and that's the way they would develop their personalities," he recalled in a recent interview. "So Kermit and Piggy and Gonzo and Fozzie and Animal, all their personalities were developed in some very blue, adult ad-libbing, and it was some of the funniest stuff.

"We call that the other side of the Jim Henson Company that the public has never seen, but we all know what it is."

Audiences in Toronto will get a taste of the company's "other side" on Tuesday when Mirvish Productions starts running the Canadian premiere of Henson's improvised comedy show "Puppet Up! -- Uncensored" at the Panasonic Theatre.

The adult-oriented show features 85 of the company's puppets, but not the iconic ones fans have come to love.

Rather, these are the Henson Miskreant Puppets -- "the troublemaker puppets ... that never could get on to the Muppets," said Henson, the company's chairman.

"Don't call these guys the Muppets."

As such, they don't have designated names or personalities -- those traits change every night, depending on the on-the-fly scenarios audience members suggest.

Another unorthodox element: the audience gets to see the puppeteers with live musical accompaniment .

As the puppeteers perform the characters centre-stage and out in the open, they don't look at each other to play out the scenes. Instead, a camera that's fixed on them projects their actions on video monitors they watch so they know what each other is doing.

The actual puppet show is simultaneously projected onto giant screens on either side of the stage.

"We call it two shows in one, because you get a rare opportunity to see how Jim Henson puppeteers work as well as being able to see the result," said Henson.

For the puppeteers, it's an immense challenge having to improvise without looking directly at each other, said comedy star Patrick Bristow, the show's co-creator and host.

"In improv, it's very important to have that eye contact, because so many subtle communications happen there. So it's forced the puppeteering improvisers to be the best ... ear listeners that they can possibly be, because that's their way of connecting with each other."

"It's like chewing gum and doing a hula hoop with a chicken on your hand," said puppeteer Leslie Carrara-Rudolph, who has been in the show and earned an Emmy nomination for performing the fairy Abby Cadabby on "Sesame Street."

Bristow will sometimes bring audience members onstage to perform in a sketch and even operate a puppet, which can sometimes lead to outrageous moments, such as the time a man proposed to his girlfriend.

"The puppets were acting out the proposal and the woman is watching and she's not sure what's going on, because she knows the puppets are playing her," said Bristow.

"When she realized that it was actually a proposal, she just lost it. We were so worried like, 'What if she says no?' We had a champagne toast ready to go and everything like that. I aged about six months in three minutes. She did say yes."

Henson called it an R-rated show, and he doesn't recommend it for audiences under 16.

"We are not shockingly adult. We don't try. In fact, we try to be classy when performing scenes," said the director/writer/producer, whose dad shot many projects in Toronto, including "The Great Santa Claus Switch," "Fraggle Rock" and "The Jim Henson Hour."

"But we allow the audience to make any suggestion as to where the scene is going in lots of places during the show, and the audience, particularly if they're really enjoying the show, will start offering very adult suggestions and we have to do it."

That subversive, darker side harkens back to Jim Henson's "wicked sense of humour" and his early work that was more adult-targeted and "anti-establishment," said Henson.

"My dad had a very adult sensibility, even when he was developing characters for 'Sesame Street.' Some of why those characters last forever is they were developed with an adult sensibility, but then they spoke in a way that the kids could understand."

His dad also didn't have a reverential attitude towards the puppets, said Henson.

"If you get precious about the puppets, then you start getting precious about the content and then maybe you can do a different kind of comedy, but you sure can't do the kind of comedy that the Henson company does.

"And really, our irreverent, subversive tone of comedy comes from the fact that we are not reverential about the puppets. We make fun of them. They are a bunch of fabric and ping-pong balls and that's part of what's funny about them.

"When I was a kid, the old puppets, once they were kind of used up, he would just throw them into toy boxes at home. So we would play with them in the sandbox and ruin them, rip them to pieces."

"Puppet Up! -- Uncensored" runs through Nov. 3 in Toronto.