Why does the naughty pop star, who sings songs you'd never hear in Sunday school, sport a Jesus tattoo? And did this daughter of two Evangelical ministers really write "I Kissed A Girl," a bi-curious ode to sexual experimentation?
"Sometimes I do things, you know, that people don't expect, like pop girls to do," she tells CBS News anchor Katie Couric. "Sometimes people would expect, well, they're pastors. I'm a black sheep."
At 24, Katy Perry is more like a cash cow. She is pop's reigning princess, thanks to that cherry-Chapstick chart-topper that spent seven weeks at No. 1 -- tying a Capitol Records milestone previously held by the Beatles.
So what about "I Kissed a Girl"?
"I woke up one morning, and I had this chorus in my head," she tells Couric. "And you know I was like 'Hmmm. That is so interesting. What interesting subject matter.'"
Ironically, it was the one song her record label wanted to ditch.
Perry: They said, "No. We don't really hear it … I don't think we're going to put this on the record." And of course I was like, (sigh) "Count to 10. It'll grow on them, just like it grew on you."
Couric: And you have actually kissed many a girl?
Perry: Yes, ma'am. I have. Many a woman.
Couric: And liked it?
Perry: Well, yeah. I guess I would have stopped after the first one.
With pin-up girl looks, and a salacious sense of humor, the singer says she's "super blessed." And she should know, given the Santa Barbara, Calif., house she grew up in.
"I went to church on Sunday morning, Sunday evening, and Wednesday night," she says. "I started singing in church at 9 years old."
Katy was raised Katheryn Elizabeth Hudson, a middle child, by two parents --both traveling ministers, whose services included speaking in tongues.
"You know, there was a movie or a documentary called 'Jesus Camp III.' And I watched it and I was like, 'Oh my Gosh. I didn't know they had behind-the-scenes footage of my childhood,'" she exclaims.
Her parents were so devout, deviled eggs were called angeled eggs and secular music was off limits. There was an exception: Katy was allowed to listen to the soundtrack from "Sister Act 2."
So how did Katy Perry get to where she is now? It turns out the apple didn't fall far from the tree.
Her mother went on a date with Jimi Hendrix and her father hung around with 1960s counterculture icon, Timothy Leary.
"He was part of the Strawberry Fields Forever," Perry says about her father. "[But] they found God, you know? They needed to find God. Not that they needed to find God, God found them, really."
At 13, the preachers' daughter was ready to take her own walk on the wild side. Katy discovered Queen - and the band's flamboyant leader, Freddie Mercury.
"He seemed to have come on stage like a firecracker. And I love that. He was an entertainer. You know? And that's what I want to be, is an entertainer."
It wasn't Queen's "Bohemian Rhapsody," but her performance on Christian television had people singing her praises. And soon enough, she was Nashville-bound. Her debut album was titled "Katy Hudson."
"It was a Christian gospel album I made when I was 15," she explains. "You know, that was my world. And I appreciated it. And all those songs I wrote were very important to me at the time. I wrote about everything I knew then."
But the record flopped, and Katy went home.
"At 16, I was just like, "OK, well this is over. What do I do now?' I watched VH1 and I saw Glen Ballard. And he was talking about Alanis Morisette's 'Jagged Little Pill' and I was like 'Well, that's a really good record. She speaks from my perspective. I want to make a record like that!'"
Six-time Grammy Award-winning producer Glen Ballard remembers the day the starry-eyed songstress arrived at his L.A. studio.
Glen Ballard: I was a million miles away working on something else.
Perry: And I walked in with my guitar. And I played him a song.
Ballard: She played the song and it was OK, that's all I need to know (laughs).
Perry: And then he called me the next day and said "I want to move you to Los Angeles. I want to help fulfill your dreams."
So not to be confused with actress Kate Hudson, Katy Hudson changed her name. After three years of writing and recording, Katy Perry was signed -- and dropped -- by two major record labels.
"I had someone say to me that 'Psst, you should probably go home, because you're never gonna get signed again. You're pretty much damaged goods. And you should be in the defect aisle at Ross,'" she says with a laugh. "And I'm 20 at that point. I'm like, 'I'm defected goods already?'"
But Ballard still believed. "I encouraged Katy to not so much rebel against anything she's been through, but to actually use it toward defining who she really was as a person."
She got it. And in November 2007, a kitschy rant called "Ur So Gay," about a metro sexual ex-boyfriend, became an instant hit with everyone - except gays.
Perry: The song is about a boy that probably was gay in another lifetime but is now straight. And I'm dating him. And he doesn't even like boys. But I think he was gay at one point in my lifetime.
Couric: But it wasn't an indictment against gay people or homosexuality?
Perry: Not at all.
What it was, was Katy Perry putting the world on notice: she had found her voice.
"It's like my very honest, frank, you know, female perspective -- very female perspective -- I guess you would say. Probably the biggest ingredient in my recipe is humor."
Her humor pushes the limits, as Couric found out when she made a backstage stop on Katy's recent "Jingle Ball Tour," and the singer pulled out a sexy Santa outfit.
What do her parents think of her music today?
"I understand that maybe they're not singing along with everything, but they are very happy for me," she says.
And to dispel any myth they may not be, Keith and Mary Hudson made a cameo appearance as mom and dad in Katy's "Hot N' Cold" music video.
"I think I'm not exactly what I was born into, but I still have my roots," she says. "[I] appreciate it and respect it to the fullest. I do believe in faith. And I believe that faith is pure."
And that, she says, is the reason for that tattoo -- a constant reminder that no matter where Katy Perry goes, Katy Hudson is never far behind.
"And I knew I wanted this on me, because no matter how much changes around me or how much I change, there's not really an eraser for this."
And every time she plays the guitar, "It stares right back at me. It's like "Remember, you came from this. And you can always go back to it (laughs)."