07/22/2009 at 01:00 AM EDT
How good are the two of you at keeping each other's secrets?
"We're both really good at that," says Selena. "It's equal. We both know when we say something is a secret, it's a secret."
What happens if the two of you happen to like the same guy?
"We've never had that—fortunately," says Demi. "I'm very protective of our friendship, so I think I'd be like, 'You can have him because I don't want to ruin our friendship.' Then she'd be like, 'No, you can have him,' and then we'd end up not liking him."
If you have an argument, how do you resolve it?
"Selena's very calm," says Demi. "I can be, like, fuming mad and I'll go, 'Selena, I'm very upset right now,' and she'll just sit there and take it and go, 'Okay, I'm going to work on it and I'm sorry.' The first time she did that I was like, 'Uh, really? I'm sorry.' So that's what we do. If one of us is upset with the other we just tell each other. Our friendship means so much to us that we're not going to let anything ruin it. We'll just work it out."
What kind of professional feedback do you give each other?
"Demi's a perfectionist," says Selena. "But she knows how to criticize herself in a healthy way. When I do something that she thinks isn't right, she knows how to say it in a way where I get it. We harmonize all the time together, and it's a big honor when I get a compliment about my music or my voice from her. She has a phenomenal voice. If she says, 'Oh, your voice has gotten so good,' it really means something to me because I know she means it."
How often do you guys talk to each other on any given day?
"We're not the type of friends where we have to talk every day to keep our friendship alive," says Demi. "We could go for a week or two, and we'll still know we're each other's best friends. It's nice to have that because a lot of times people expect you to call and text every day, and I don't have a schedule that permits that."
Do you share each other's clothes and stuff?
"I have her jeans from seventh grade in my closet and her Madonna
shirt that she's worn a thousand times," says Selena. "When we borrow, we don't really ever give it back, but we don't care. She'll be like, 'Is that my shirt?' And I'll be like, 'Are those my jeans?' And then we'll be like, 'Eh, whatever.' She had my makeup for like six months one time, and I was like, 'Oh yeah, I was missing that!' "
Is there an embarrassing story that the two of you always laugh about?
"Growing up together we always used to pose in front of the mirror, aspiring to be on the red carpet like any little girl would do," recalls Demi. "We came up with this pose where we'd hook arms. So the first time we were on the red carpet together they were like, 'Demi! Selena! Pose together!' So we did our pose and all the photographers were like, 'Uh, yeah...could you not do that?' We were so embarrassed."