The superstar played a stripped down version of her song "Blank Space" at Max Singer and Kenya Smith's reception in Long Beach Township on Saturday as amazed guests looked on and sang along.
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Swift agreed to attend after getting a letter in April from the groom's sister.
She wrote about how her brother was a huge fan and how he and their ailing mother had danced to Swift's song after the newlyweds were married in a hospital room. Singer's mother died shortly thereafter.
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Swift had contacted Singer's sister and they planned the surprise visit.
Swift also presented the couple a special card that stated: "So It's Gonna Be Forever," a lyric from "Blank Space."
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