The 23-year-old singer and her close pal and tourmate, Nick Jonas, are opening up about their friendship in a candid new Q&A for Billboard magazine, in which no topic is off limits. The two have been tight since their Disney days, and are comfortable discussing just about everything from their love lives, to Lovato's struggles with mental health and addiction.
In 2010, Lovato infamously left the Jonas Brothers tour early after she punched a dancer in the face, prompting her to check into rehab. Jonas now admits he was "angry" at Lovato at the time.
"[I thought] that we were going to get sued," Jonas, 23, says. "I mean, it was bad. On top of losing a friend, we have seven dates left, it's a big production, people are expecting to see Demi and that's not going to happen. I was angry, because a week before I pleaded with her to confide in me. We talked on the plane for two hours."
"After treatment, I had to have some time sober before I wasn't embarrassed to talk to him," Lovato admits. "Nick says I sent text messages, but I don't remember sh*t. The first time we saw each other since that tour was my [2012 Los Angeles] concert at The Greek. We caught up right before the show, then performed. It was an emotional reunion -- I got one of my best friends back."
These days, Jonas says he is allowed to drink alcohol around Lovato, though he puts up his own limits.
"She gave me the right to have a drink around her, but I'm never, ever drunk around Demi," he stresses.
Clearly, the two aren't afraid to be brutally honest with one another, particularly when it comes to their romantic relationships. The "Confident" singer reveals she gives Jonas -- who's rumored to have had a fling with Kate Hudson -- advice to "have a lot of fun" as opposed to tying himself down.
"He's a guy in his 20s and he's famous and he likes to have a lot of fun," Lovato explains. "Listen, even when he was in a relationship, I was like, 'Get out of that. You could f**k anybody that you want right now, so have fun and do that.'"
"The tricky thing is, from what I've heard, I'm a bit emotionally unavailable," Jonas adds.
"I go, 'Honestly, I didn't like her anyway,'" Lovato laughs. "It's not because she's mean or anything, but he has such a great sense of humor and I want him to be with someone that makes him laugh. I can tell if something's up because he'll close off."
As for her own recent breakup with ex Wilmer Valderrama after six years together, Lovato says she's definitely open to finding love again.
"It's not on my mind, but I welcome anything," she says about getting back into the dating scene. "I'll have fun. But a relationship ... I won't want that for a long time."
... And she also isn't looking to get into another big Twitter beef anytime soon. Lovato briefly quit Twitter last month after getting some heat for throwing shade at Mariah Carey while defending Ariana Grande. The singer says she never heard from Carey's people about the incident, nor that she expected to.
"I'm sure she's sitting on diamond records not giving a f**k what I have to say," Lovato muses to Billboard. "That's fine. I don't even give a f**k what I have to say. That's why I just say it."
"The woman is mean for no reason," Lovato wrote about 46-year-old Carey last month, commenting on a meme suggesting Grande was a Carey wannabe. "Extremely talented? Yes. Superhuman? Possibly. Unnecessarily rude? Absolutely."