First, a congratulatory advertisement in the London Evening News to congratulate Margaret Thatcher, saying “May the Fourth Be with You, Maggie. Congratulations.”
Then In the 1988 episode of Count Duckula, “The Vampire Strikes Back”, a space-faring superhero, Tremendous Terrance, asks Duckula the date and is told, “May the Fourth”. As Terrance departs, he tells all below, “May the Fourth Be with You.”
Astrophysicist and author Jeanne Cavelos used the saying on page 94 of her 1999 book The Science of Star Wars.
In 2008, the first Facebook groups appeared, celebrating Luke Skywalker Day, with the same catchphrase.