The singer and actress opened up about her experience for a promo video during auditions in Providence, Rhode Island.
When asked whether being a judge had been what she expected, Lovato said: "I mean, one, I definitely didn't think that it would be this challenging because saying no to people is really hard and emotionally it kind of messes with you a little bit 'cause you don't want to say no to some people, and then some people you're torn and you know in the back of your mind that if you say no, what if that was their only shot and you let them go when they weren't really that bad?
"It's just really confusing. But it is everything that I expected and more, with having fun and just bonding with the cast and everything. Like, everyone's so sweet and awesome and the crew's amazing, so I'm having a lot of fun."
She later added that having Britney Spears as a co-judge was helpful, commenting: "We're both new at this, so we're not feeling like it's just one of us is the new kid in school - it's like we're both new and we're both adjusting, and so it's really nice to have somebody that gets it, and is like 'Ah, I'm nervous' on the first day."
Lovato also spoke about her rumoured romance with One Direction's Niall Horan, explaining: "No, I'm not [with him]. He's really sweet and he's one of my really good friends now.
"But I'm single at the moment and I plan to be for a long time because I need to focus on my career and myself and my wellbeing before I think about getting in a relationship with anyone."
Watch the interview with Demi Lovato below: