Jean-Baptiste Frédéric Isidor, Baron Thielemans, (known professionally as Toots Thielemans), was a Belgian jazz musician, renowned for his virtuosic harmonica and guitar playing and brilliant whistling, as well as his many compositions. He emigrated to the US in 1951 and became an American citizen in 1957. In the early 1960s he recorded his composition, Bluesette, which immediately attracted immense popularity among jazz improvisers.

Throughout his career he appeared with the top jazz artists of his era such as Benny Goodman, George Shearing, Bill Evans, Oscar Peterson, Dizzy Gillespie and Quincy Jones among others. His music was featured in various films including Midnight Cowboy (1969) and Looking for Mr Goodbar (1977). He also composed the theme song for the long-running television series, Sesame Street. In 2009 he was awarded the title of Jazz Master by The National Endowment for the Arts, acknowledged as the highest honour for an American jazz musician.