The 22-year-old singer stopped by The Tonight Show Starring Jimmy Fallonon Thursday and opened up about why things with Mendes were initially "weird" when they went from friends to boyfriend/girlfriend.
"It's so funny because when we first started going out it's so weird... [dating] somebody who was your friend for a really long time... It's kind of weird in the beginning," she admitted. "It took me, like, two months to be able to call him 'baby.' I didn't want to say his name because we were dating and I couldn't say 'baby,' so I'd just be like, 'Hey! You! Hand me that water over there?'"
"It's weird, but it's great," Cabello added of starting a romantic relationship with a friend. "... The people around you already know them because you've known them for a long time, so it's just like, 'Now we kiss and hold hands.'"
Cabello also stops by The Ellen DeGeneres Showon Friday and reveals she had a "crush" on Mendes years before they made things official.
"I for sure had a crush... We were stupid. I think we both had a crush, but were being babies about it," she admits. "But we're grown now! But I definitely, definitely, definitely had a crush."
While Cabello is fairly candid while discussing Mendes, the "Liar" singer is a little more guarded while performing with her beau. When she and Mendes took the stage for a steamy version of their hit "Senorita" at the 2019 American Music Awards, for instance, she held back from kissing him, instead lovingly rubbing her nose against him.
"We practice it and then I kiss because I kiss him, but then it's, like, onstage it just feels weird because I know people are expecting it," she explains. "... So then that's why I hit him with my nose."
Regardless of if she's comfortable physically expressing that love onstage, Cabello is definitely up to doing so through her music, and her new album, Romance, which is out now.
"It's about being in love. I was basically completely single for 20 years and it was, like, the intensity and adrenaline of my life was in the studio writing about an emotion that I wanted," she shares. "Whereas this time, it's just been a lot that's happened. You know, I've fallen in love, out of love, and in love. That's basically what this album is about, just kind of falling in love and what that feels like."
ET's Katie Krause caught up recently caught up with Cabello, who opened up about what she's learned about love while working on her album.
"Ironically, I feel like so many of these songs are about being in love and about how you feel about another person," she shared. "But I think the biggest thing I've learned is that ... as cliche as it sounds, you have to really love yourself and know yourself first."
"The most important relationship that you'll ever have is actually the one with yourself, and then comes the ones with other people," she added.