Paul Allen Wood Shaffer, CM (/ˈʃeɪfər/; born November 28, 1949) is a Canadian-American singer, actor, voice actor, author, comedian, and multi-instrumentalist who served as David Letterman's musical director, band leader and sidekick on the entire run of both Late Night with David Letterman (1982–1993) and Late Show with David Letterman (1993–2015).