Familiar face from the telly - and familiar voice from the radio - throughout his career, Tiernan has appeared on The Tommy and Hector Show (alongside Hector Ó hEochagáin). Eagle-eyed among you will remember him as Father Kevin in Graham Linehan's Father Ted. Since then, he's been all over the place: The Lee Mack Show, Micahel McIntyre's Comedy Road Show and Dave's One Night Stand.
Award-wise, he's been just as prolific, having won Channel 4's So You Think You're Funny? award in 1996, the Perrier in 1998 and the Best Stand Up at the British Comedy Awards in that same year.
In 2003, he won the Nokia Best of the Fest Award and the Orange People Choice Award at the Edinburgh Fringe Festival. In 2006, he won Ireland's Funniest Living Person Award at the People of the Year Awards. If that doesn't convince you, we don't know what will.