Ji Byung Soo, a 77-year-old social worker, is going viral for his performance of Son Dam Bi's "Crazy."

On the March 24 episode of the long-running KBS talent show, 'National Singing Contest,' grandpa Ji dominated the stage with the cover of "Crazy." He perfected not only the vocals but also the choreography in his own unique way.

Video of his performance quickly went viral and even caught the attention of Son Dam Bi herself. The singer-actress also shared a performance video in an expression of appreciation

She stated, "I've prepared a dance in response as I'm greatly thankful and awed by the passion of grandpa Ji Byung Soo from Jongno district. Please live a long healthy life, grandpa!"

Meanwhile, netizens commented, "Omg he is so cute," "You're never too old for anything," "Grandpa got moves," "I love this!"