They became well known during the late 1920s to the mid-1940s for their slapstick comedy, with Laurel playing the clumsy and childlike friend of the pompous bully Hardy. The duo's signature tune is known variously as "The Cuckoo Song", "Ku-Ku", or "The Dance of the Cuckoos".
It was played over the opening credits of their films and has become as emblematic of the duo as their bowler hats. Their most notable films are The Lucky Dog (1921), The Second Hundred Years (1927), The Music Box (1932), Babes in Toyland (1934), and Block-Heads (1938).