'Star Wars' Day: May the 4th Be With You

— -- "Star Wars" fans have a big reason to celebrate today.

May 4, or, "May the 4th Be With You," marks a celebration of all things "Star Wars."

(Yes, it's a pun. In case it's not obvious, it's a take on the popular line from the film, "May the force be with you.")

According to Starwars.com, the unofficial holiday was first marked in 1979 after Margaret Thatcher won the election to become Britain's first female prime minister.

"To celebrate their victory her party took a half page of advertising space in the London Evening News. This message, referring to the day of victory, was ‘May the Fourth Be With You, Maggie. Congratulations,’ further proof of the extent to which 'Star Wars' has influenced us all," wrote author Alan Arnold, according to the website.

May is an notable month for the popular franchise: The original "Star Wars" premiered on May 25, 1977, and its creator, George Lucas, will turn 72 on May 14.

Lucasfilm is a subsidiary of Disney, which is the parent company of ABC News.