Before Michael Rosenbaum was handed the role of a twentysomething Lex Luthor on the WB's new Superman saga Smallville (premiering tonight at 9 pm/ET), producers issued him a stern ultimatum. "They pretty much said, 'If you want to be Lex, you've got to shave your head,'" the chrome-domed actor tells TV Guide Online. "I tried on a bald cap, but I looked like a conehead. So I said, 'Alright. Let's be a man about it. Let's shave it.'"

Truth be told, Rosenbaum — who previously worked for the WB as a star of the short-lived comedy Zoe, Duncan, Jack & Jane — would have gotten his bikini line waxed if the plum part called for it. "It took about a week for it to settle in," recalls the 29-year-old New York native of his first days playing one of pop culture's most famous bad guys. "I was on the set and saw a truck that said Luthor Corp., and the license plate on my Porsche said 'Lex Luthor'... I thought 'I'm [expletive] Lex Luthor!' I mean, that's a dream!"

Of course, reality soon set in when the up-and-comer remembered that he'd be portraying a character originated on the big screen by two-time Oscar-winner Gene Hackman. However, that initial panic eventually gave way to a cool confidence. "How do I fill his shoes? I don't," he insists. "I just do my own thing." Luckily, aside from their memberships to the Hair Club for Men, Rosenbaum's Lex and Hackman's Lex share little in common. In addition to the obvious age difference, new Lex won't be as one-note rotten as old Lex (think Anakin Skywalker pre-Darth Vader).

"We're going to follow Lex on his journey to becoming evil," explains the star of the upcoming Animal House-like farce Sorority Boys (due next spring). "But as of now, he's just an ambitious, charismatic, misunderstood guy." And if Rosenbaum has it his way, you'll be able to add "hysterically funny" to that list. After all, given Smallville's dark tone, someone will have to lighten things up — and who better than the show's resident goofball/prankster.

"I think you're going to be surprised by how much personality I bring to him," winks the sprightly thesp. "In a later episode, he might even throw a big party at his house."