Take a look some of the latest trailers to The Rum Diary and you might expect to see something like The Hangover 3. Surely if we lifted the curtain here we'd find a grinning Galifianakis. While The Rum Diary has its share of red-eyed late night binges, it's also story about a sullen young man struggling to find his voice, inspired by a novel written by Hunter S. Thompson himself.

Although Johnny Depp plays the journalist in question, this is not Fear and Loathing in San Juan. The Rum Diary was based on the gonzo journalist's own experiences in Puerto Rico in the late 1950s. The main character Paul Kemp can be seen as a stand-in, a place holder for the man who Thompson would eventually become. The question is, do you want to spend two hours watching Depp playing a writer in search of himself?

Johnny Depp, left, and Aaron Eckhart in The Rum Diary. (Film District/Associated Press)

Kemp arrives in San Juan looking for a paying gig and experiences to fill up the novel he can't seem to finish. Scamming his way into job at the local paper, Kemp finds himself penning horoscopes and following around Sala, a photographer with more than a little Gonzo in him. While Kemp digs into the local history of American exploitation, in comes Sanderson, a slick PR type played by Aaron Eckhart with echoes of his Thank You for Smoking persona. Soon Kemp's caught up in a land scam deal Sanderson's orchestrating, while falling for Chenault, his free-spirited girlfriend.

Although Johnny Depp and H.S.T. were close friends in real life, the dapper actor is a strange choice to play the embryonic version of Thompson. With his camel-coloured slacks and polo shirts, Depp looks like an extra from a Banana Republic photo shoot. It's as if Kemp is the Clark Kent, the mild-mannered persona of the man we thought we knew. But other than a few muttered lines - about bastards and an "accusatory giblet" - we're denied the pleasure of seeing the true Thompson emerge.

Instead it's as if writer and director Bruce Robinson has taken components of Thompson's character and split them among three characters. There's Kemp as the introspective young man; Sal, the gravel-voiced man of appetites played by Michael Rispoli; and finally there's Moburg, a shambling, filthy, moonshine-swilling mutant played by Giovanni Ribisi in an battered trench coat and nasal whine worthy of Ratso Rizzo.

The Rum Diary is a series of vignettes in search of a story. There are moments when it coalesces into something greater, including a scene in a steamy late-night dance hall rocking with rhythm and blues and a deranged chase on Puerto Rican backroads, but these are not enough. Those hoping to see Bruce Robinson return to Withnail and I form will be disappointed with this disjointed ode to the man Kemp would become.

RATING: Two empty mini-bar bottles out of five.