Conan O'Brien was a prankster during his Harvard years, but he also credits his success to hard work in the classroom.

The late-night TV host spoke to an audience of Harvard University students on Friday about the value of a liberal-arts education and about his time at the Ivy League school. Harvard President Drew Faust hosted the discussion with O'Brien, who graduated from Harvard in 1985 with a concentration in history and literature.

O'Brien sharpened his comedy chops while working for the Harvard Lampoon, the school's storied humor magazine. Among his college pranks, O'Brien says he stole the outfit worn by Robin in the '60s TV show "Batman" when it was displayed on campus. But he also fondly recalled classes on city planning and U.S. history.

"College is when you should actually get about as lost as you can get, in terms of expanding what you know," he told the audience.

He's still an avid reader of history books, he said, with an interest in figures like Winston Churchill and Andrew Jackson.

O'Brien encouraged students to try new pursuits without worrying about mistakes. But he warned students that, even after gaining success, insecurities don't go away.

"It's an illusion that people in my situation have figured something out. It is a constant struggle," he said.

The conversation ranged from his Harvard thesis to the status of women in comedy, who he says are "dominating." He joked with Faust, once saying that his studies did "absolutely nothing" for his career, and added a quip about the high cost of tuition at Harvard (he joked that it's $26,000 a year; it's actually $45,000).

Asked about his biggest regrets, O'Brien said he still kicks himself for shying away from an economics class because it intimidated him.

"That was knowledge that I don't have, and I've always regretted it," he said. "I wish I had taken that course."