Actress Kaley Cuoco is used to playing the popular girl on ABC's 8 Simple Rules. But her latest role in ABC Family's Crimes of Fashion (Sunday, 8pm/ET) casts her as a fashion student who — despite a great sense of style — is more geek than chic. While navigating the ever-changing world of hemlines, Cuoco's character, Brooke, discovers that her long-lost (and recently deceased) grandfather was a mob boss. Worse yet, his Mafia family wants her to fill his shoes! They're not exactly Jimmy Choos, so she steps in the only way she knows how. Jokes Cuoco: "She makes this little mob her own — and fashion-tabulous!"

Playing an inexperienced (and unconventional) mob boss was a perfect fit for Cuoco, since the 18-year-old is completely clueless about Mafia dramas. Before filming, she didn't even know that her costar, Dominic Chianese, plays Uncle Junior on HBO's The Sopranos. Talk about out of the loop.

"I don't watch The Sopranos and Dominic doesn't watch half-hour comedies, so he had no idea who I was either. We were both screwed!" she recalls, laughing. "He said, 'I'm taking a chance on you!' and I said, 'Well, I'm taking a chance on you!' It was really funny."

While Cuoco's new to the TV-crime genre, she admits she's had a run-in or two with the law. "I have so many speeding tickets," Cuoco reveals. "It was a yearlong process trying to get them off my record. I had to go to driving school and I had to do community service by speaking at schools. I'm like the biggest dork, trying to tell these kids about my career and they have no idea who I am. It was all major punishment so I'll never speed again!"

Speaking of her career, we asked Cuoco for a sneak peek at the new season of 8 Simple Rules, which returns September 24. "Bridget was in Washington, D.C., and comes back with a really big secret that is going to drag on for many episodes," Cuoco says. A secret? In Washington? Get out!