He is a member of the classical crossover group Il Divo, who have sold over 30 million copies worldwide discs.

[1] His musical training started at the age of five, when Bühler began singing in a choir and also learned to play violin, clarinet, piano, guitar, and drums.

[2] His progress in the field led him to move to Amsterdam, where he studied voice at Sweelinck Conservatorium with Udo Reinemann, a well-known German baritone.

He sang in the choir of the Dutch opera and performed in the Salzburg Festival under the direction of Claudio Abbado.

In December 2003, Bühler became a member of the international musical quartet Il Divo along with Carlos Marín (Spain), Sébastien Izambard (France), and David Miller (United States).