Lou Costello was an American comedian and actor who was best known for his work in the comedy duo Abbott and Costello. He was born Louis Francis Cristillo in Paterson, New Jersey in 1906 and began performing in vaudeville in the 1920s. He met Bud Abbott in 1936 and the two formed a successful comedy team that went on to become one of the most popular acts in show business. Lou Costello was known for his physical comedy, slapstick humor, and catchphrases such as 'Heeey-A-Baba-Looey!' and 'Who's on First?'. He died in 1959 at the age of 52.