Find out why Lovato envied her fellow former Disney star.
Staying sober takes plenty of hard work.
Demi Lovato reinforces this message in a new interview with Cosmopolitan magazine for their September cover issue, in which she admits to envying her fellow former Disney star, Miley Cyrus -- specifically, when it comes to the outspoken singer's ability to party. Demi has been open about struggling with addiction issues with drugs and alcohol in the past, entering rehab in 2010.
"There was a time when I was jealous of people who were able to party," Demi reveals. "For instance, Miley -- in her music video 'Can't Stop,' her whole thing was partying and not giving a f**k. Part of me was super jealous that I couldn’t be like that. I had to look at my life and be like, 'Okay, that's just not what you can do. There's no need to be bitter about it.'"
WATCH: Demi Lovato on Being a Role Model and Staying Strong in Recovery
The 22-year-old "Cool for the Summer" singer has often credited her boyfriend, 35-year-old Wilmer Valderrama, for keeping her on the right track, and shares that he didn't give up on their relationship even when he was advised to.
"We started dating when I turned 18 ... Right after that, I went to rehab," she shares. "People told him, 'You should probably leave. She's on a spiral, and you're going to be sucked down with it.' But he was like, 'I'm not leaving. This is somebody I really care about.' We relate on a lot of levels."
NEWS: Demi Lovato Gushes Over Wilmer Valderrama: 'He Never Takes Credit for My Sobriety'
"I've seen a lot of s**t," she adds. "S**t people don't know about. He's seen a lot of stuff too."
And luckily for her, the former That '70s Show actor isn't the jealous type.
"Nick [Jonas] and Wilmer get along great -- Joe [Jonas] and Wilmer too," she says. "It's weird. In the beginning, I was like, 'Why the f**k are you friends with Joe [Demi's ex-boyfriend]?' He was like, 'He's a cool guy.' Yeah, I know. I dated him."
But aside from her five-year relationship with Wilmer, right now Demi is currently focusing on her new music ... and once again compares herself to edgy artists like Rihanna and Nicki Minaj.
"There are a lot of girls in pop. They have badass lyrics, but I feel like I’m the only person other than Rihanna and Nicki Minaj who isn't afraid to say, 'Try something on me and I'll f**king beat your ass,'" Demi says bluntly. "There are people who can dress up and play the part, but their music doesn't say it."
WATCH: Why Demi Lovato's Friendship With Miley Cyrus Ended
Last month, ET caught up with Wilmer at Comic-Con, when he predicted some pretty bold things about his girlfriend's future.
"I think Demi is on a path for, you know, mega-stardom," Wilmer said. "I think she's gonna redefine pop culture in a level that people can't even expect next year, for sure."
Watch below:
