Taylor Swift Crashes this wedding... But how did the bride's sister make it happen?

"Congratulations Max and Kenya!!" Swift captioned a duck-lipped pic of herself with Singer, Smith and some of the night's guests.

Swift's appearance at the wedding was no coincidence. The groom's sister Ali reached out to the singer in April, writing Swift a letter about her about her and Singer's mother's death. While the big wedding took place on Saturday, Singer and Smith actually married in his mother's hospital room so she could be a part of the occasion before she died. The groom and his mother even chose "Blank Space" as the song for their mother-son dance.

While this wasn't the first fan wedding for Swift -- she is notorious for surprising her fans and crashed a set of nuptials last year -- this time, she also doubled as a wedding singer. The 26-year-old performed 'Blank Space' on the piano for the newlyweds' first dance as a tribute to the groom's mother.

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