It took six months for Nick Caraway to expose the great Jay Gatsby as a social fraud.

When Mashable business editor Todd Wasserman tweeted a link to a purported movie poster for the 2012 Great Gatsby remake directed by Baz Lurhmann, redditors debunked the myth in a matter of hours.

The poster, a closeup of stars Leonardo DiCaprio and Carey Mulligan in embrace, was taken from a leaked photo of a rehearsal session in 2010, noted Redditor BillyCloneasaurus. "Somebody has just plopped text on the top."

What's worse, the unidentified artist made hasty work, picking a photo that left DiCaprio's ticket-selling face off the poster and failing to mention The Great Gatsby's production as a 3D film.

"The real poster will have that in large, bold letters," wrote redditor IndianaLetItGo.

Poor grammar on the poster's subtitle, which reads "Based off [sic] the beloved novel by F. Scott Fitzgerald," was a "dead giveaway," thought johnnytightlips2.

As many noted in the course of the Reddit thread, the proper wording is either "based on" or "based upon,” if, as Anothernerd81 noted, “you want to be formal/British.”

"It makes no logical sense to say something is ‘based off’ something," wrote Berjiwhir, a self-identified teacher. "You have a base, the thing is designed to sit on that base to add to that base, but it's ‘off’? Based on. Not based off."

For his next film, Baz Lurhmann should retell the story of detective Sherlock Holmes and cast the entire film with redditors.