The 26-year-old singer performed a stripped down version of 'Blank Space' when Max Singer tied the knot with Kenya Smith after months of co-ordinating the surprise appearance with the groom's sister Ali.
Video footage of the performance was shared by Gage Simmons, who wrote: "So Taylor swift showed up to my cousins wedding... #Surprised (sic)"
The bride's sister Ashley tweeted: "REMEMBER WHEN TAYLOR SWIFT CRASHED MY SISTER'S WEDDING (sic)"
And another guest shared a selfie with the star and wrote: "So @taylorswift13 just came to my cousins wedding (sic)"
The wheels were set in motion for the performance in April when Ali wrote to Taylor - who recently split from Calvin Harris after over a year of dating - to tell her about the death of her mother, how Max and Kenya had wed in hospital before she passed away so their mom wouldn't miss out on the big day, and the groom even danced with his sick parent to 'Blank Space'.
And as well as her surprise appearance at the celebrations, which took place at the Brant Beach Yacht Club in Brant Beach, New Jersey, on Saturday (04.06.16), the 'Shake It Off' singer gifted the couple a hand-made card, writing
'So it's gonna be forever' in watercolours with a floral circle.
Taylor herself shared a number of photos from the day, captioning one of herself with the bride and groom: "Third wheel"
She wrote alongside another: "Congratulations Max and Kenya!!"
It was recently claimed Taylor had hoped to marry Calvin.
She said: "She used to talk about their future a lot - marriage, babies. And although he wants all of that, it just felt a bit like she was all full-steam ahead, whereas he is more of a slow and steady, let things progress organically, kind of guy."
Despite this, the insider suggested there is no lingering animosity between the pair.
Of their relationship failure, the source said: "It's a shame because Taylor is a lovely girl. But it just obviously wasn't meant to be."
