"Joe Dirt" and his glorious mullet are back ... and David Spade took a selfie to prove his classic 'do will be front and center for the new flick.
You may recall ... the 2001 film ended with Dirt's mullet being replaced with dreadlocks -- but it looks like that's all changed for the new movie set to debut next year on Crackle.
Spade captioned the pic, "Day 1. Let's get this s*** started! #imjoedirt #whatscrappenin."
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