It's not a national holiday, yet it might be an intergalactic one.

May the Fourth, as in "May the Fourth Be With You" has become a day to celebrate all things Star Wars, especially following last year's revival of the series with "Star Wars: The Force Awakens."

One the stars of the current Star Wars trilogy, Daisy Ridley, appeared in a YouTube video surrounded by some of the series' characters to deliver well wishes from the cast of "Star Wars: Episode VIII," which is set for release next year.

Like many Star Wars characters, "May the Fourth" comes with an interesting origin story. One of the earliest known references to the day followed the May 4, 1979, election of Margaret Thatcher as Britain's prime minister, according to a post on the official Star Wars website. Thatcher's party took out an ad in the London Evening News with the message, "May the Fourth Be With You, Maggie. Congratulations," the website said, adding that the day took off once the Internet began connecting fans.

The day has been a trending topic on social media. Comedy Central's "@midnight" got things started by launching a #StarWarsSongs hashtag, asking fans to come up with Star Wars themed song titles. Some of the responses include "Whiskey in the Jar Jar" and "When You Wish Upon a Death Star."

NASA got in on the fun with a blog comparing real planets to the ones depicted in Star Wars, including Saturn's moon, Mimas, which has become known as the "Death Star" moon thanks to its distinctive crater.

Retailers are trying to turn fan enthusiasm into a profit. Many, including Wal-Mart, Target and Toys 'R' Us are offering promotions on Star Wars related items this week.