Beyond that, the Irish comedian - who is now joining the likes of Alan Davies, Dylan Moran, Ardal O'Hanlon and Bill Bailey, by starring in his own sitcom - candidly admits that "stand-ups are often not as versatile as actors. But we're lucky in that our profile gets us work which our talent normally wouldn't justify. I know people who are far better actors than me who aren't even getting auditions. I don't know how deeply producers are trawling the world for performers."
However, the very limitation of some stand-ups can work to their advantage when it comes to casting for sitcoms. Jerry Seinfeld, for instance, would probably never be asked to play King Lear, but could you imagine a more ideal figure to front a sitcom about a wiseacre New York comedian? "Some stand-ups can only be funny as their stand-up personas," says Tiernan. "But if they're cast as that, it's perfect. Look at Dylan Moran in How Do You Want Me? He fits that character like a glove."
But what Tiernan is doing in Small Potatoes is slightly different. He has toned down the expansive stand-up persona he usually employs to play Hewitt, a more understated, fully-rounded character. Hewitt is an acerbic under-achiever who could just as easily have been played by an actor as a stand-up. A graduate, he is slumming it by working in a video shop. Looking at a customer's gold credit card, he tells him, "I was going to get one of those. Filled out the form. Didn't have enough money for the stamp."
"I know I can be funny on stage, but I wanted to try and translate that on to TV in different roles," Tiernan explains. "There's more subtlety to being funny on TV. Sometimes in sitcoms you're told to be bigger, but I hate overacting so I tried to avoid that."
Tiernan is branching out from stand-up in other ways, too. He is currently writing his first novel, a brooding affair "about a not very successful stand-up who decides to unite people through sorrow rather than laughter. Scott Capurro and Ardal O'Hanlon have also written dark novels. I think it's because stand-ups spend so much time appeasing people that we nurture this stinking, sulphurous devil on our shoulder, and handed the opportunity, we can't wait to give vent to him. It's a Ying and Yang thing. It confirms the cliche of the comic who wants to play Hamlet."
Tiernan, who is currently hosting The Stand Up Show on BBC1, is also working on his own comedy programme for C4. But, he hastens to point out, "it's not a simple case of filming my live act. You have to adapt the whole style for television - like Jonathan Demme did with his film of the stage show Swimming to Cambodia.
"In fact," Tiernan continues, deadpan, "we've approached Demme to direct my show. He understands that it's just a pilot at this stage, but he's committed to the project."
For the time being, though, Tiernan sees no end to the popularity stand-ups are currently enjoying on TV. Commissioning editors are inviting them to appear on everything from travel programmes to Question Time.
"They think we're show people," Tiernan reckons. "To them, we're Mr Saturday Night. There's a whole range of opportunities for stand-ups now. Someone who can walk out in front of a thousand people and make them laugh is someone who will obviously be equally comfortable standing in front of a Ferris wheel, juggling monkeys, while saying `Don't go changing. We'll be right back after the break.'
"In Ireland, they're now getting glamour girls rather than serious meteorologists to present the weather. If that continues, in a couple of years I'd like to see myself reading the news."
`Small Potatoes' Tue 10.30pm C4; `The Stand Up Show' tonight 11.45pm BBC1Reuse content