The Hollywood hunk and star of the upcoming "Dune" remake flaunted his hot bod in a series of photos ... where he's caked in mud ... giving a thumbs up while trying to clean him off.

Jason captioned the pics ... "like a pig in sh**." He added ... "hard to explain this one. but i had an amazing day. now i need a dune buggy. dune coming soon aloha j."

The actor's dune buggy escapades clearly are designed to promote the new feature adaptation of Frank Herbert's science fiction novel ... which costars Rebecca Ferguson, Zendaya, Timothee Chalamet, Dave Bautista, Josh Brolin, Oscar Isaac and Javier Bardem.

But, who really knows -- or cares. Bloody Marys are a good idea for heading into the weekend ... but might we suggest Muddy Momoas instead?