"If you're alone, I'll be your shadow. If you want to cry, I'll be your shoulder. If you want a hug, I'll be your pillow. If you need to be happy, I'll be your smile. But anytime you need a friend, I'll just be me." --Anonymous

Taylor Swift and Kellie Pickler certainly embrace that friendship philosophy. When The Boot caught up with the best buds and touring partners backstage at a concert in Columbia, Md., the two talked about each other as if they were related. Kellie, abandoned by her own mother when she was just two years old, even refers to Taylor's mom as 'Momma Swift.' She returns the favor by being the older sister Taylor never had.

We pick this talented twosome's brains about what being "BFFs" means to them.

How did you two meet?

Taylor Swift: Kellie and I met and got to know each other on the Brad Paisley tour. I was 17 and she was 20, and we were both on our first albums and one of our first tours. The way that the Paisley tour worked was that he had three opening acts, and it would alternate in rotation every night. One of us would go on first, one of us would go on last. So, one of the first things that bonded us was she got a kitten -- the cat that she has now, Pickles -- and she needed someone to look after her kitten when she would go on to play. She would leave the kitten with me or my mom. Then we started hanging out all the time, talking about boys, and just became fast friends.

Kellie Pickler: I officially adopted her as my little sister. She's so smart. She's very talented. It was really cool to be able to write together, record together and shoot a video together.

What's your favorite thing about each other?

TS: My favorite thing about Kellie is that she's the one person on the planet who has the nerve to delete a guy's number out of my phone if she doesn't think he's right for me [laughs]. She will grab my phone and delete his number, because she does not want me to talk to someone who she thinks is bad news.

KP: When I say she's like a little sister to me, it's really true because we both keep each other in line. I have a younger half-sister, but we didn't grow up together, and we never saw each other. I've actually seen Taylor more than I have my real sister, so she really is like a little sister to me.

What's the best part of touring together?

KP: It's good to be out on the road with friends. This business can be very lonely, because we're always on the go. Every day, you wake up in a different city. So it's good that we wake up to good people. Everybody gets along. It's like being on the road with family.

I have the most fun with Taylor after the show, when we can just sit in our PJs and talk. It's just girl talk, you know? It is like that whole sister kind of feel. I really cherish the small things, when we're not doing anything but enjoying each other's company. We were just on the bus talking about interior decorating. We talk about shopping and clothes and shoes and guitars ... we talk about normal things.

Do you trust each other with your deepest, darkest secrets?

KP: Absolutely! It's important to surround yourself by people you can trust.You don't want yourself exploited to the world. Everybody has to have that. Taylor and her mom, they know a lot about me. I call her mom Momma Swift. She's very good to me.

TS: I can trust Kellie with all my secrets because she's really unbiased. She'll give me advice from a place that she knows. She's learned a lot of lessons, and she knows a lot for her 22 years of being on this earth. She's the person who will very bluntly say to me, "Get over it!" ... instead of my friends who are like, "Maybe he misses you or maybe he didn't mean it that way, or blah, blah, blah." Kellie will just look at me and say, "He's bad news, get over it."

Do you ever have a crush on the same guy?

TS: We never have a crush on the same guy because we're attracted to different kinds of people [laughs]. Kellie never, never thinks that the guys that I think are cute are cute. I have a really eclectic, weird taste in guys, and she just never ever agrees with it.

KP: We're attracted to totally different people. She and I are nothing alike when it comes to boys. I feel like an old soul [laughs].