Sorry, 'Back to the Future' fans: That Michael J. Fox sequel you saw on Facebook isn't happening

Michael J. Fox went from being one of the biggest TV stars in America (thanks to his lead role on Family Ties) to one of the most beloved movie stars in the world with 1985’s Back to the Future, Robert Zemeckis’s sci-fi hit about a teenager named Marty McFly who travels back in time via a souped-up DeLorean and ends up having to make sure that his parents meet — and that he’s eventually born. Zemeckis’s blockbuster spawned two sequels, but since then, neither Marty nor Doc Brown (Christopher Lloyd) has returned to the screen. This past weekend, however, the internet was rocked by what seemed like a game-changing announcement.

On Saturday, an unofficial Michael J. Fox Facebook fan page published the below message, accompanied by a photo of Fox, Lloyd, and Lea Thompson (aka Marty McFly’s mom) together — proof, supposedly, that the trio really were hard at work on a new installment of the Back to the Future franchise:

Twitterverse quickly got caught up in the excitement:

Unfortunately, the notion of the cast reuniting for Back to the Future IV turned out to be a hoax.

As you can see from the caption on Thompson’s Instagram pic, the photo dates back to 2015 (from a London Comic Con Back to the Future 30th anniversary celebration). And that revelation, along with the initial post’s spelling errors, eventually tipped off fans about the phoniness of this announcement, which has since been deleted.

All of which confirms a familiar rule — always be wary about what you read online, especially when it involves long-coveted dream projects that sound too good to be true.

Read more from Yahoo Entertainment:

• Eric Stoltz on missing out on ‘Back to the Future’

• ‘Back to the Future’ DeLorean from sketch to screen

• Michael J. Fox sees Parkinson’s fight as ‘one of the greatest gifts in my life’

• Lea Thompson recalls the woes of ‘Space Camp’

Watch: Lea Thompson on how makeup transformed her in Back to the Future: