Many years ago I saw a very interesting music documentary series on TV which I think was called What Is Music? Bobby McFerrin was featured in a couple of segments. He was conducting an orchestra while singing along to the music. I was very impressed by his talent so I bought his CD called Paper Music, Bobby McFerrin / Saint Paul Chamber Orchestra

It's brilliant and beautiful.

This info from his website mentions my two favourite pieces of music from the album:

"Released in 1995, Paper Music was Bobby’s first classical album, and featured him both conducting and singing with the St. Paul Chamber Orchestra to fascinating and beautiful results. The same voice that climbed the pop charts, redefined vocal jazz, and invented an entirely new a capella vocabulary is equally at home replacing a cello in a Vivaldi Concerto, or singing Faure’s haunting melodies.

"Bobby was appointed Creative Chair of the St. Paul Chamber Orchestra in 1994, and this album beautifully marked the beginning of his second career as an orchestral conductor."