McCartney died in a car crash and to spare the public from grief, the surviving Beatles replaced him with the winner of a McCartney look-alike contest, sometimes identified as "William Campbell" or "Billy Shears". Afterwards, the band left messages in their music and album artwork to communicate the truth to their fans. These include the 1968 song "Glass Onion", in which Lennon sings "here's another clue for you all / the walrus was Paul", and the cover photo of their album Abbey Road, in which McCartney is shown barefoot and walking out of step with his bandmates.

Rumours declined after an interview with McCartney, who had been secluded with his family in Scotland, was published in Life magazine in November 1969. During the 1970s, the phenomenon was the subject of analysis in the fields of sociology, psychology and communications. McCartney parodied the hoax with the title and cover art of his 1993 live album, Paul Is Live. In 2009, Time magazine included "Paul is dead" in its feature on ten of "the world's most enduring conspiracy theories".