The fact that Johnny Depp is a big fan of the late “father of Gonzo journalism” Hunter S. Thompson is no secret.

Depp played Thompson’s alter-ego, Raoul Duke, in Terry Gilliam’s Fear & Loathing in Las Vegas, narrated Alex Gibney’s documentary Gonzo: The Life and Work of Dr. Hunter S. Thompson, and was a good friend of the real Thompson – enough so to finance his private funeral, where the late writer’s remains were shot out of a canon, along with a collection of fireworks.

This fall’s The Rum Diary sees Depp tackle yet another of Thompson’s aliases: Paul Kemp, a New York journalist who travels to San Juan, Puerto Rico, in order to work for a local paper and instead raises hell, fueled by booze, lust, and a desire to upend the status quo.

Oscar-nominated actor/writer/director Bruce Robinson (How to Get Ahead in Advertising) adapted Thompson’s original Rum Diary book for the big screen and directed the flick. Joining Depp on his latest crazed adventure are the likes of Amber Heard (Drive Angry), Aaron Eckhart (The Dark Knight), Giovanni Ribisi (Lost in Translation), and Academy Award-nominee Richard Jenkins (The Visitor).

Check out the trailer for The Rum Diary below:

One thing should be obvious, after watching that preview – Fear & Loathing in Las Vegas this ain’t. That film has earned a cult following for being as stylistically warped and out-of-control as its characters and subject matter; Rum Diary looks positively normal by comparison, as far as Robinson’s filmmaking aesthetic goes.

This is still a Hunter S. Thompson tale and Robinson looks to have captured the outlandish nature of the story and its participants. Whereas Fear & Loathing dealt with the eventual decay and self-destruction of the 1960s counter-cultural movement, Rum Diary takes place at its onset. Hence why the latter film looks like much more of a “eat, drink, and be merry” affair, with scenes full of reckless behavior, heavy drinking, carefree sex, and just about every other hippie stereotype you can think of.

Depp clearly has his Thompson shtick down pat at this point, complete with rumbly voice and oddball mannerisms. The actor’s take on the Duke character from Fear & Loathing is quite famous, having even been the inspiration for his animated character, Rango (see below). However, Depp’s version of Thompson’s Kemp persona could actually feel like less of a caricature and more of a fully-realized character, in comparison.

Rum Diary won’t be a smash at the box office, but it will be one of the most non-mainstream projects that Depp’s taken on in recent memory. For people who were fans of the eccentric actor long before the first Pirates of the Caribbean movie essentially made him a household name, it’s a welcome return to form.

The Rum Diary is scheduled to roll into U.S. theaters on October 28th, 2011.