What's that tiny dot on a US comedy-scape that is being dominated by scores of productions from the juggernaut that is the Judd Apatow stable (excellent as they often are)? Why it’s Ben Stiller and his proper actor chums with a great big budget and a great big silly concept...

'Tropic Thunder' is the film, and, although it doesn't quite live up to its brilliant trailer, it's not half bad.

Stiller plays action movie hero Tugg Speedman and, while he hasn't quite created an equal for his brilliant Derek Zoolander, his fading action hero seeking credibility has comedy mileage – not least thanks to Stiller's talent for playing shallow egotists with exactly the right hint of vulnerability to make you buy in.

The other comic creations - Jeff Portnoy (Black), a familiar sounding comedy actor who plays all seven fat people parts in one movie, rap star/wannabe actor Alpa Chino (Jackson) and stock 'war movie actor with the kid who gets shot look' (Baruchel) – also serve their purpose, yielding a few laughs without setting any comedy records.

Kirk Lazarus (Downey Jnr) is the final member of the motley crew contracted to make the 'movie within a movie' (which is also called 'Tropic Thunder') that the film takes as its starting point. The story – a bunch of whinging actors making an 'Apocalypse Now' type war movie are mistakenly dropped into the wrong part of the jungle and run into a bunch of real-life drug barons whom they mistake for extras – does the job of moving events along but is predictably incidental.

Initially a savagely accurate Russell Crowe satire (sample line: 'being an actor is a lot like being a rugby player', delivered in pitch perfect pompous Crowe mode), he changes gear all too soon, getting an operation to 'method act' a stereotypical black Vietnam movie platoon sergeant.

Robert Downey Jnr playing Russell Crowe, playing a black platoon sergeant, is just not as funny as Robert Downey Jnr playing Russell Crowe.

Steve Coogan, as the film director, Nick Nolte, as the Vietnam vet who wrote the book on which the film is based, and Matthew McConaughey as the desperate agent also appear and, though McConaughey sometimes errs slightly on the side of the 'wink wink, nudge nudge' school of spoof acting, they generally fit in well.

A special mention must go to he performance of Tom Cruise; going on the hair alone, he was presumably one of the main models for Stiller's character – who is simply brilliant as crazed studio boss Les Grossman.

But this is all about the jokes and while the humour is at times resistably puerile (if 'resistably' isn't a word, it should be) , there are enough hits – the opening sequence of spoof trailers for Speedman and Lazarus' next projects is almost worth the price of admission itself – to keep most people happy.

For some there may be a slight taste issue; for example, the joke built around the suggestion by Downey Jnr’s character's suggestion that Tugg Speedman had failed to win any awards for his film 'Simple Jack' because he went 'full retard' (as opposed to the 'half retard' Lazarus had perfected on his way to multiple gongs) may prove too much.

Others, myself included, will be happy to treat it as pointed skewering of the 'How To Win An Oscar' approach to acting, rather than a poor taste joke about disability.

Overall, while the quality control is occasionally not quite as tight as you might like, this is an enjoyable comedy.

Brendan Cole

Check out our 'Tropic Thunder' premiere gallery here.