Michael Bublé sings in subway

Michael Bublé says his impromptu subway show was a "dream come true".

The singer shocked commuters by giving a performance underground in New York City on Thursday. He was scheduled to play a gig to celebrate MTA's expanding wireless service but it was cancelled after a press conference was held to reveal the Boston bombers' plot to target Times Square.

Michael was clearly looking forward to the performance, so decided to go ahead and sing at a station anyway, reports New York Post.

He travelled to the Lincoln Center/West 66th Street stop for an a cappella show, where he was joined by a backing group called Naturally 7.

"This was a dream come true for me. Once you've sung in the subway waiting for the No. 1 train, you know you've made it," he smiled.

Michael's set left subway users "gobsmacked" as they waited for their trains. During the performance he delivered a rendition of the Jackson 5 hit Who's Lovin' You, which appears on his latest album To Be Loved.

Michael is believed to have played his whole set list as planned and relished the experience.

"I feel like a real New Yorker now," he beamed. "Singing in the New York subway is something that's been done for years and years and years and I feel like it's the most authentic, organic way to make music."