The path from devoult christian schoolgirl to playboy centerfold is bound to be a complicated one full of twists and turns. FOR jenny McCarthy, it's been a ride worthy of a brand new memoir, where she... See More
The path from devoult christian schoolgirl to playboy centerfold is bound to be a complicated one full of twists and turns. FOR jenny McCarthy, it's been a ride worthy of a brand new memoir, where she comes clean about her religious roots. She took abc's juju chang back to the house where she grew up in for a trip down memory lane. Oh, my god. This is so sweet. It's so sweet to look back. Reporter:HERE, DRIVING Down the streets of chicago's south side -- I grew up on the second house to the right and my basketball hoop is still up in the backyard. Oh, my god. Everything looks smaller. Reporter: Jenny mccarthy's path ill lum nates who she's become. The basement is where satan lived. Reporter: We showed up unannounced. Hig, how are you? I used to live here. Yes, I do know. You do know that? And this is "nightline." I hope you don't mind. Reporter: Going with mccarthy to her childhood home takes her bam to her humble roots. She grew up very fast in the public eye as a sexy pinup girl. But in her bedroom, she was deeply religious. We used to lay are rosaries and statues all over our body because we thought that would protect us from satan. And when we fell asleep, I would steal them off her to me. I used to have a jesus poster, the pope was over there. Flaming heart of jesus was over there. And then I had some "i love jesus" t-shirts and bags hanging up. Reporter: Truly, jesus was your bieber. He was my bieber, all right. He still is. You know, jesus. Reporter: She became a household name, co-hosting "SINGLED OUT" IN THE '90s. But has kept her claim to fame these dames as a six-time "new york times" best-selling author. Her latest is all about her childhood, growing up poor. We really were hungry a lot of the nights. Reporter: And quite pius. This is the church I went to twice a week Reporter: Both left a deep MARK on McCarthy. Your whole life has been about fear. Fear of going to hell or fear of poverty. Yeah, it has made me work harder and I think everybody needs motivation. I used to put on talk shows. And this was my audience. I would have the chairs lined up like this. Reporter: She has always been driven and especially these days, as a single mom to her 10-year-old son, evan. I wouldn't be nearly as driven if I wasn't a single mother. If I had somebody to depend on financially, I might slow it down a bit, but no. I am a workhorse. Reporter: You really are. I am. Reporter: You have so much going on. Thank god, yeah. God. Reporter: Yeah. Sinners can have a place in this world. Reporter: But despite her RELIGIOUS UPBRINGING, McCARTHY Was a rebel. She worked for a grocery store for five years and it was here -- they moved the register! Reporter: That she figured out her way out was to pose for playboy. Guys would come in to buy them, they would ask for them, i pick it up, throw it at them. That gave me the idea. These chicks can do this. Why couldn't i? Reporter: And she did. Just 21 years old. Eventually, she was named playmate of the year. When hef said, you're pl playmate of the year, I went, oh, my god, yes. And then, oh, my god, no. I cried for an hour that I was playmate of the year because i thought, now that really -- that really ensured my entry into hell. Reporter: Extreme little devout christians who straddled multiple jobs to send their four daughters to catholic school, her parents were distraught. My mom was the one that was like, I don't -- I only have three daughters now. That's like -- cuts. Reporter: Ouch. And I cried and I was like, i begged her, I was like, listen. You raised me to be a good person. This was my only option. I will be a playmate that does something great, mom, trust me. Stanby me. Reporter: And they did. when McCarthy got that $100,000 check for being playmate of the year, she gave the money to her parents and moved them to the suburbs. To them, you know, I could see what bittersweet feels like. They cried. They were happy and sad, all at the same time because they didn't envision the daughter having to do that to he them out. You know? Reporter: She moved to hollywood and grew disillusioned with her faith but used it when touring as playmate of the year. Guys would be like, so, you know, what are you doing after this, you're so beautiful. I think that, you know, we have this connection that we should maybe walk on the beach later. And I would go, well, as long as we can also bring jesus, my savior. Reporter: Still, she admits that she was broen to using men to get through difficult periods of her life. Did you use men as a drug? I would say yes. But not sexually. I would use them as distraction for my own life. For instance, when evan was diagnosed with autism, I quickly got into a relationship, just to distract from the pain that i was going through, so I got in a relationship with jim carrey at the time and really allowed my mind to t caught up in, you know -- Reporter: The romance. The romance, to numb, to numb really what I was going through. Reporter: She turns 40 next month and after a long-term relationship with carrey and recently are brian urlacher, McCARTHY IS SINGLE AGAIN. She still doesn't believe in god, but that doesn't mean she's given up on her wild side. You constantly break this sexy girl stereotype by being smart and savvy and then you go and pose for playboy again. Crazy. Reporter: What's up with that? Stereotyping is the biggest mistake you can ever do on anybody. I am an amazing mother. I am an amazing, I think, author and workhorse. And I'm also an amazing, like, fun, want to be sexy kind of Reporter: For "nightline," I'm juju chang in chicago.
This transcript has been automatically generated and may not be 100% accurate.