The day after she won album of the year at the Grammy Awards, he posted a sweet message on social media to his "beautiful girlfriend."
Congratulations to my beautiful girlfriend pic.twitter.com/qfZ12i4IBd— Calvin Harris (@CalvinHarris) February 16, 2016
Swift took home three Grammys on Monday night, including best pop vocal album for "1989" and best music video for "Bad Blood."
She celebrated her Grammy wins with Harris later that night at Hyde nightclub in Los Angeles.
The 26-year-old pop star and 32-year-old producer/DJ have been dating for about a year.