Image copyright Taylor Swift / Instagram Image caption Swift posed for photos with the couple

Pop star Taylor Swift surprised one of her biggest fans by turning up at their wedding over the weekend.

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.

As the wedding guests danced, the star emerged to play her hit song behind a small electric piano. Several guests captured the performance on their phones, while others simply sang along.

Swift also painted a watercolour card for the couple, featuring the Blank Space lyric "so it's gonna be forever", and stuck around to pose for photos with the wedding party.

The singer later uploaded a picture of herself with the bride and groom to Instagram, captioning it "third wheel".