But there are a couple of modern-day mysteries surrounding the story, too. First, a Paramount source says the film, called The Lost City of Z, doesn't have a script yet and no date to start production has been set. In addition, Fawcett didn't have a beard, but a handlebar moustache.
"There is no film-related explanation I can give you as to why [Pitt] has the beard," the Paramount source tells PEOPLE.
If it's not for the role, perhaps the hunky-turned-hairy A-lister is just trying to keep his chin warm in the winter? Or perhaps he's using the beard to help teach his kids how to braid?
Whatever the reason, the biggest question of all is, just how long will it get?
Who knows – unless there's a script for the life story of ZZ Top secretly circulating in Hollywood.