Ruggero (or Ruggirero) Leoncavallo (April 23, 1857 - August 9, 1919) was an Italian opera composer. His two-act work Pagliacci remains one of the most popular works in the repertory, but the most famous part of the opera is Vesti la giubba, which has been used on the Disney Channel animated series Phineas and Ferb in the episode "Raging Bully."