Hilary Duff and Joel Madden aren't as unlikely a couple as you may think. At least that's what they're saying in the new issue of Teen People, for which they posed for their first cover together.

"You're automatically prejudging us because Joel has tattoos or I have blond hair," Duff told the magazine. "He has tattoos so he's bad, I smile all the time so I'm perfect."

"[People] think I'm this crazy guy," Madden said. "I went to the ATM and this lady backed away, and Hilary asked me, 'What is it like when someone scoots away because they're scared?' I never notice it, she notices it for me."

So to set the record straight, Madden isn't a bad influence. He hangs out with Duff's mom, even when his girlfriend isn't around. He covers Duff's butt when she bends over if she's wearing low-cut jeans. And he's been drug- and alcohol-free for the past two years. In fact, Duff's usually the one who has to drag Madden off the couch to go out at night. "I'm the most normal, low-key, sit-at-home, watch-TV type," he said. "She's made me more social, 'Come on and hang out with my friends!' It's not me going, 'Come on, Hilary, get on a motorcycle and ride into the sunset to a raging party!' "

"And when we do get in the car, he's always the one who says, 'Put your seatbelt on!' " Duff added.

The couple revealed their long-rumored relationship two months before Duff turned 18 (see [article id="1506032"]"Hilary Duff, Joel Madden Go Public With Lovestyle Of The Rich And Famous"[/article]). Since then, they've become more comfortable dealing with public perceptions, especially regarding the fact that Madden started dating Hilary when she was underage and that there's an eight-year difference between the two of them. "I didn't care what the press would say," Madden said. "I cared what my mom would say."

The couple says they have the same maturity level -- Duff says Madden sometimes acts like a teenager and Joel says Hilary is wise beyond her years. "We're on the same level, even though he's so much older," Hilary told the magazine.

But they certainly don't have the same level of experience, which is why they're taking it slow. "Joel is the most respectful boyfriend I've ever had," she said. "We had five or six dates before we even kissed."

"This is the slowest relationship, physically, that I've had," Madden said. "It's grown at the right pace, organically and naturally."

They're also in no rush to get engaged or elope. "We think about the future, but not marriage," Madden said. "I just hope we're always happy."

"I don't ever think about being apart from Joel," Duff said. "We just feel so comfortable with each other, and we know we're not going anywhere."

Still, Madden let it slip that if he had a daughter Hil's age, he wouldn't let her date a guy his age. "I wouldn't let it happen," he said.