The pun was first used back in 1979, with Britain's Conservative Party congratulating Margaret Thatcher in print for taking the prime minister post that day.
According to Canada's Globe and Mail newspaper, the first organized "Star Wars" event on May 4 took place in 2011 at the Toronto Underground Cinema.
The next film in the "Star Wars" universe -- "Star Wars: The Last Jedi" -- opens nationwide Dec. 15.