Just when you thought every variation on the Christmas-themed film had been attempted, along comes another (in glorious 3D, no less) which manages to make you simultaneously warm, festive and repulsed.

This third instalment finds our two lead characters somewhat estranged from each other, due to their now divergent lifestyles. While Harold (John Cho) has become a married, successful businessman, Kumar (Kal Penn) is still an aimless, habitual pothead (a world which in reality is far removed from actor, who also moonlights as a White House intern!)

Their paths cross again when a mysterious package for Harold causes his old stoner BBF to pay him an unexpected visit, resulting in the huge Christmas tree which sits centre stage at his pristine residence being destroyed. To avoid facing the wrath of Harold’s Xmas-obsessed father-in-law  (Danny Trejo, decked out in a Xmas woolly jumper which is almost worth the price of admittance alone) the duo head off into the city (with Harold’s work colleague and young daughter, plus Kumar’s horny housemate in tow) in a desperate attempt to find a replacement. They manage to get tangled up with a variety of shady characters and increasingly outlandish situations, whilst rediscovering that true meaning of Christmas and how it can bring absent friends together once more.

Where many features in this modern age of 3D work hard at ensuring the effect is as unobtrusive as possible and subtle within the storytelling, much of the fun here is derived from how the makers gleefully draw attention to the format at every available opportunity (perhaps as a spiky reminder of how gimmicky it can become in the hands of lesser filmmakers). Objects fire across the screen in grossly exaggerated slow-mo and the sheer volume of 3D artists tasked with creating the copious chronic smoke effects in this film must have seriously trumped all those involved in bringing the vast world of Pandora to life.

Crude, lewd and as vehemently un-PC as ever, a large part of the film’s success is witnessing all of that content juxtaposed with a colourful, almost traditional looking seasonal family-friendly film, right down to the sappy soundtrack and the bright, garish colours which burst all over the screen (that’s not the only thing to explode everywhere either). Just when you let your guard down and you’re intermittently fooled into thinking you’re in the middle of some cloying, sentimental Christmas flick, another outrageous set-piece (happily) drags you back down to the film’s puerile, gross-out level.

This is a film which knows its audience inside out (some of the US-centric references tend to grate at times, however) and while a couple of gags fall a little flat, the majority hit the filthy, bodily fluid-encrusted mark. Neil Patrick Harris also returns for a show-stopping surrealist song and dance scene, and above all, this is ridiculous, knockabout absurdist stuff (a sequence even takes place in Claymation after the duo trip out having knocked back spiked eggnog) which is the perfect antidote to the saccharine Christmas fare it cheekily parodies.

In a nutshell, if your idea of a fun evening at the cinema is watching an infant inadvertently being introduced to (and ingesting) the gauntlet of recreational drugs out there, this is the perfect film for you. Merry Christmas everybody!