Jim Parsons making a "Big Bang" on Broadway

(CBS News) Jim Parsons -- best known for his role as theoretical physicist Sheldon Cooper in the breakout CBS sitcom, "The Big Bang Theory" -- says he's not smart enough to be nerdy and geeky.

"I'm probably more dorky," said the two-time Emmy winner and Golden Globe winner.

Pictures: Jim Parsons
Pictures: 2012 Tony nominees

Parsons is currently preparing for a stint on Broadway in the play, "Harvey." It's the story of a mild-mannered man who has an invisible friend that resembles a 6-foot rabbit.

"Specifically with "Harvey," this character is such a good person," he said. "He's such a warm person. He tries to connect with other human beings. For me, playing somebody at my day job [Sheldon on "The Big Bang Theory"], who is the opposite of that... It was a no-brainer."

Parsons' "Big Bang" is ending its fifth season with a big finale that involves a wedding and space travel -- but he is mum on any of the episode's surprises.

What's it like dealing with all of the scientific jargon on the show? Parsons says it can be complicated.

"I spend a great deal of my time simply memorizing," he said. "And when they create changes in the dialogue close to tape night, I spend a great deal of my time in a fit of anxiety. But... the writers tend to put it in a way that there's a certain... rhythm to it. And once you've latched onto that rhythm, those words come out of your mouth."

"The Big Bang Theory" season five finale airs on Thursday, May 10, 2012, on CBS.

Preview performances for Harvey will begin May 18, 2012 at Studio 54 with an official opening scheduled for June 14. The revival is set to run through Aug. 5.

For the full interview, watch the video above.