Mario Bertolazzi was an Italian conductor, composer and author.
Sometimes he used the pseudonym Colt J J.
During his studies he became passionate about jazz, in particular to trumpeter Bix Beiderbecke, attending the shows also in Milan and thus knowing, through his fellow citizen Gian Carlo Testoni, the Circolo del Jazz Hot in Milan; then he obtains a recording contract with La Voce del Padrone and publishes the first 78 rpm in 1938.
In the 1950s he approached pop music, and was often an orchestra conductor, as well as author and composer of television shows, including La Bella Epoque (directed by Eros Macchi, 6 episodes from 23 March 1957 to 4 April 1957) and especially Un due tre, with Raimondo Vianello and Ugo Tognazzi, and radio, as Solo contro tutti (written by Dino Verde and Garinei & Giovannini, from 1959).
In the 60s he often collaborated with Marcello Marchesi, for which he composed some music, as well as conductor in some comedy TV shows.
In 1971 he collaborated with the Quartetto Cetra, composing all the music and directing the orchestra in the television broadcast Stasera Sì.