Taylor Swift surprised a 96-year-old fan with a memorable Christmas gift – a live performance in his living room.

The Shake It Off star shocked World War Two veteran Cyrus Porter unannounced as he celebrated the festive season with his family in Missouri on Boxing Day (Monday 26 December).

Taylor Swift
Taylor Swift brought "Swiftmas" to Cyrus Porter, 96, who recently lost one of his daughtersTwitter

A long-time fan, Porter is also known as "Swifty" within the local community, and had been previously raving about the singer to local news outlet KFVS news.

"I've been to two concerts. Memphis and St Louis," he told the station. "Look what she does...she puts on a show no one else puts on...I just liked the way she did stuff."

The interview went viral and seemingly reached the Grammy winner, who is among one of the most followed celebrities on social media.

The artiste delivered a surprise acoustic rendition of "Shake It Off" accompanied by Porter and many of his 20 grandchildren.

Swift, 27, later stayed to meet and chat with close to 60 relatives for more than an hour, report E! News.

"My Popo was ecstatic! He was grinning from ear to ear and even had tears in his eyes," family member Caroline Fowler told the media outlet.

"The first thing he said to her was 'How did you get here?' He loved every moment. He told her how he was proud of his family, his country and Taylor Swift!"

It came at a particularly difficult time for Porter, who had recently lost one of his daughters.

"It was the best day ever and our family is thankful for this!" Fowler added. "It meant so much for the family to see him so happy!"

Family member Robert Frye added on Twitter, "It's a Christmas Miracle!!! Thank you @taylorswift13. My grandpa was so excited! Won't be able to get the smile off my grandpa's face for months."