American comedic duo made up of Bud Abbott (William A. Abbott, 1896–1974), born in Asbury Park, N.J., and Lou Costello (Louis Francis Cristillo, 1908–59), born in Paterson, N.J.; partnership began when vaudeville comedian Costello's regular straight man fell ill and Abbott, working in the theater's box office, offered to substitute; played straight man to Costello's buffoon from then on; radio debut 1938; on Broadway in 1939's The Streets of Paris; first movie, Buck Privates (1941), with eight other comedies following in the next two years; known for several vaudeville routines, particularly “Who's on First?”, a farcical baseball commentary performed on radio and television that was made into a popular recording.