Blake Shelton turned Michaal Buble's song 'Home' into a country hit.  Now Buble is taking the Jackson 5's song 'Who's Lovin' You' and reworking it.  He gave a surprise performance of the song in New York City's subway with the acappella group Naturally 7.

After the performance, Michael said, 'Singing in a New York subway is something that has been done for years and years and years, and I feel like it's the most authentic, organic way to make music.'

I feel acappella music is the best way to hear if someone can REALLY sing.  There's no instruments to hide behind.  It's just you and your voice.  And Michael Buble CAN REALLY sing!

Buble's version of 'Who's Lovin' You' is on his new album, 'To Be Loved,' that came out last Tuesday.