To make matters even better, former One Direction star Niall Horan was also at the event, standing on the table with the pair. He was later filmed jamming out with Mendes, Cabello and Scottish up-and-comer Lewis Capaldi to Capaldi's song, "Someone You Loved."
Though there was plenty of after-party love, Mendes and Cabello spent the majority of the GRAMMYs separately. After each walked the red carpet solo, Cabello gave a moving performance of her new song, "First Man," in honor of her father, who was seated in the audience.
For more GRAMMY performances, watch the clip below: