Iconic theme was first met with Spielberg's laughter

It’s arguably the most instantly recognisable musical score in movie history, but when Steven Spielberg first heard John Williams's now iconic theme, the Jaws director thought he was joking.

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Upon hearing the classic two-note phrase for the first time, Spielberg, exhausted from a difficult shoot off the coast of Martha's Vineyard, questioned if the composer was serious.

Williams had sat at the piano and played just two alternating notes to represent the unseen menace of the shark. Spielberg laughed, but Williams doubled down.

The two-note motif-a minor second interval, in technical terms - was later performed by a tuba and various orchestral sections. It would come to define the atmosphere of Jaws, building suspense, and signalling danger even when the shark was not on screen.