Many celebrities have publicly supported marijuana legalization in recent years. But certain celebrities have promoted cannabis for many, many years. Willie Nelson, Cheech and Chong, the Grateful Dead and many others are well-known pot connoisseurs. But there’s one band who jumped on the legalization 50 years ago: the Beatles.

On July 24th, 1967 the Beatles and their manager Brian Epstein signed their names on a full page ad in the London Times advocating for marijuana legalization. The ad was a response to the arrested of acclaimed photographer John Hopkins, who was later sentenced to nine months in prison for marijuana possession. The band used this as evidence that the United Kingdom’s policies were unnecessarily harsh.

The ad argued that marijuana is “the least harmful of pleasure-giving drugs, and…in particular far less harmful than alcohol. Cannabis smoking is widespread in the universities, and the custom has been taken up by writers, teachers, doctors, businessmen, musicians, scientists and priests. Such persons do not fit the stereotype of the unemployed criminal dope fiend.”

The Beatles were just four of 64 people who signed the ad, and it wasn’t their idea to make the ad. However, Paul McCartney ended up paying for the ad himself after meeting with a pro-legalization group. McCartney supposedly wanted to keep his financial support a secret because he thought the more mainstream public might turn against the band.

While the ad didn’t lead to marijuana legalization in the U.K., it did cause a public conversation on the subject and some minor changes to their drug laws including a reduction in the maximum sentence for marijuana possession from 10 years to five.

The Beatles support for marijuana legalization shouldn’t come as a surprise to anyone who’s listened to The Magical Mystery Tour.