New Jersey couple Max Singer and Kenya Smith were celebrating their marriage when Swift appeared to play a stripped-down performance of Blank Space.
It was arranged by the groom's sister, who wrote to the star, telling her the couple had legally wed in her mother's hospital room just before she died, so she did not miss out on their big day.
Blank Space was played at the time.
Swift later contacted Singer's sister, Ali, and they planned the surprise together.
