Junee added: “Afterwards some people came up to me and told me it really was Chris Martin.
“It was amazing, it was like we connected purely through music, not fame.”
Speaking about Friday’s duet, the full-time busker from South Korea said he had given his audience of about 20 a choice between Viva la Vida and a song by The Script.
More hands went up for Viva la Vida, he said.
A Coldplay fan himself, Junee said he could not believe what happened.
He said he usually spent his days busking around Covent Garden, the London Eye and Trafalgar Square.
