Izzard decided to guest star in a multi-episode arc on Showtime's "United States of Tara" this season, because of the show's complexity.
"I normally try not to do comedies, but it's a dramatic comedy, a drama with a comedic edge. There seem to be two different types of comedies that exist these days. I thought, `Let's go do it,'" he said.
"United States of Tara," which airs 10:30 p.m. EDT Monday, stars Toni Collette as a suburban wife, mom and troubled host to multiple personalities. Izzard plays a professor who meets Tara when she decides to finish her college degree and signs up for his abnormal psychology class.
The professor's doubts about the authenticity of her diagnosis begin to waver when he sees Tara's startling alter egos emerge.
He's a complex character to explore, Izzard said.
"This guy is a broken genius. He's brilliant but has (erred) in his past, and that's why he's teaching in Kansas. I thought I could tap into that, someone who thinks that he's brilliant but the world says is not brilliant."
Collette calls working with Izzard a joy.
"I love his humor, his swagger and all that he has brought to season three," she said.
Izzard, 49, said he has wanted to act since age 7 and, at 30, "it started working."
His varied credits include the Tom Cruise film "Valkyrie," "Ocean's Twelve" and sequel "Ocean's Thirteen" and the TV series "The Riches." His stage work in London and New York is impressive, including a Tony Award-nominated performance in 2003 for "A Day in the Death of Joe Egg."
Izzard has put his own stamp on standup, delivering amalgams of wide-ranging observations and impressions while sometimes garbed in dresses. That has led people to assume he's gay, but Izzard has described himself as a "straight transvestite."
He has developed a theory that a comedian intent on an acting career has to be strategic, because he or she starts with "baggage."
"I think Jim Carrey suffered from this baggage. If you have transferred over (to drama), people say they are used to you" as the funnyman, Izzard said.
To stretch his boundaries, he has actively avoided sketch shows and most sitcoms and focused on drama or dark comedy such as "United States of Tara," which was created by Oscar-winning writer Diablo Cody ("Juno") and co-stars John Corbett and Rosemarie DeWitt.
"It's a harder way, a slower way, but this is the way I've decided to do it," Izzard said.
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