Lovato, 27, recently took to her Instagram Story to share a snap of a beautiful bouquet of flowers that Mendes and Cabello, 21 and 22 respectively, sent her.
"Hey Demi, We're thinking of you talking about how much you inspired us when we were kids," the couple wrote in the accompanying note, before signing it, "Love, Shawn & Camila."
While Lovato called the gesture "so f**king sweet and cute," she had one complaint about receiving the rose and tulip-filled arrangement.
"I also feel old now but it's totally worth it because this is so thoughtful," she quipped, referencing the slightly younger couple's message about liking her when they were children.
"Thank you guys so much! @shawnmendes & @camila_cabello," she added. "I love you both."
Lovato's post came shortly after Mendes and Cabello were nominated for Best Pop Duo/Group Performance for their song, "Señorita," ahead of the 2020 GRAMMY Awards.
In response to the nomination, Cabello gushed about being recognized alongside her "favorite person," while Mendes simply wrote, "Thank you so much @recordingacademy!"
Watch the video below for more on the couple.