But one week into filming and already a month behind schedule, Cockburn is forced by maniacal studio producer, Len Grossman (played by Tom Cruise in his best disguise), to take drastic action to save the film, inadvertently plunging his stars into the middle of real war in the process.

It is some time since Ben Stiller took such creative control over a film, with Zoolander in 2001 seeing the last time he wrote, directed and produced a comedy that showed off his clear comedic ability.

Tropic Thunder, then, is Stiller taking the same familiar steps as before, but with this second crack of the whip he has clearly become more daring and adventurous in what he feels he can achieve.

From the start of the film it is clear this is a big budget, all out comedy –– but also one that is surprisingly innovative. A series of mock trailers at the start of the film introduce its 'superstars' before a brilliantly chaotic opening sequence shows the cast attempting to film an opening sequence to their blockbuster.

The film's cast is the key to its success, with both major and minor characters all working together flawlessly without any one of them starting to steal the limelight.

Thanks to the script (co-written by Stiller, Justin Theroux and Ethan Coen) even characters with little time on screen are given a chance to shine with some of the film's funniest gags and set pieces. The best of these come from gruff, dishevelled, nonsensical Vietnam veteran Four Leaf Tayback (Nick Nolte) and Tom Cruise's hysterically psychopathic studio executive.

Robert Downey Jr edges slightly ahead of the pack as the multi-award method winning actor Kirk Lazarus, who has supposedly undergone controversial skin pigmentation surgery to allow him to play the platoon's black sergeant.

Although this makes for a minefield of political correctness, Downey Jr does a fantastic job of pointing out the absurdity of the figure he plays, filling incomprehensible, mumbling monologues with self-depricating ad-libs - all of which are underlined by the fact that he stubbornly refuses to get out of character, even when the gang realise the war they are caught up in is no longer pretend.

Tropic Thunder is not entirely without its faults, however, and a lot of the time feels like it fumbles its way between one admittedly hilarious set piece and the next. Jack Black also proves the weak link in the cast, as his drug-hooked, family film star character has the least to offer the comedy, other than one ongoing 'Film stars take drugs' jibe.

But these downfalls fail to take away from the fact that Tropic Thunder is a very daft, but very funny, film, and one which will provide plenty of laughs in return for the price of admission.

4/5