Having mainly done lighter roles in comedies like Head Over Heels and Patch Adams, Monica Potter admits that co-starring with Morgan Freeman as an embattled Secret Service agent in Along Came a Spider was something of a stretch.

"The hardest part for me was not laughing," she tells TV Guide Online. "I was always trying to turn the movie into Airplane. I got in trouble a little bit. Then Morgan would yell at me — he'd be like, 'Grim up, Potter!'"

Surprisingly candid, Potter confesses she was initially reluctant to take the role because she didn't think much of her character. "If Morgan wasn't attached to this, I probably wouldn't have done it," she says. "He's a dream. I want to work with him again, but in a comedy."

Even so, memories of her escapades as a precocious preteen did give Potter a good reference point for detective work. "I always liked Nancy Drew mysteries and the Hardy Boys when I was a kid," she giggles. "I [would pretend to be] an FBI agent. I would break into people's homes and see if they were having affairs. My sister Bridget and I thought we were Charlie's Angels. We got so busted. We walked in [the neighbor's house] and were like, 'Okay, whose underwear are these?' They were her husband's, of course."

While she says she might consider doing another suspense flick, Potter — who's currently shooting the romantic comedy I'm with Lucy — reiterates her preference for more light-hearted fare. "Comedy's my favorite thing in the whole world," she insists. "I think it's a science."