The duo is playing coy about the status of the friendship, but now Cabello, who recently split from boyfriend Matthew Hussey, is very fond of Shawn.
Speaking to Clash magazine, the 22-year-old said, "I've never had a lot of friends. I've always just had a few people in my life that I trust. I feel like it's so rare to meet someone in this industry and find a person of that quality, and I feel like Shawn is that person for me.
"I just trust him, and no matter the level of intensity that he has around his career or I have, he is just normal, and that is so rare and precious to find in this industry. To be able to hang out with someone and you don't really care that they're Shawn Mendes, you know what I mean? You're just people, and that is definitely something that is rare."
And Camila insists it felt so natural to work with Mendes on "Senorita".
"I think I've actually known him the longest out of anybody in the music industry," she added. "We've been in each other's lives for, like, four or five years, and it's been really beautiful to kinda grow up together. It's actually a really beautiful feeling to know that this person is always going to be in my life, we're always going to love each other."