The opening credits of Tropic Thunder, a ripe comedy about the appalling egos of Hollywood stars, are just delicious. A series of crisp trailers advertise the most ghastly-looking tosh Scorcher VI features the action legend Ben Stiller surrounded by molten lava, holding a baby in one hand and a huge gun in the other. Jack Black is the farting sensation of Fatties: Part III. And the multiple Oscar winner Robert Downey Jr plays the anguished monk and gay hero of an art-house hit, Satan’s Alley.

Needless to say, these self-absorbed monsters fail to bury their differences when hired to front the most spectacular war movie of all time. In a dismal attempt at cinéma vérité, the director (Steve Coogan) airlifts his squabbling stars to a jungle in the middle of Cambodia, steps on a landmine, and departs from the film in little bits.

After this promising start the satire rapidly runs out of puff. Eventually the dimwits realise that they’re A-list targets in a guerrilla-infested war zone. The grim truth has absolutely no effect on these ludicrous posers. Stiller is possessed by the spiritual honesty of Rambo. Downey is a blacked-up clone of Russell Crowe, a Method Australian loony who refuses to get out of character even when his credibility goes up in flames. Jack Black bites the head off a bat when it tries to pinch his last wrap of heroin.

This is cheap rum. The Apocalypse Now pyrotechnics clearly cost a fortune. But the pleasures of Tropic Thunder are spread as thinly as Ben Stiller. He not only stars, he directs, co-writes, produces, and undoubtedly made the tea.

The stretch marks are painfully obvious. But there is one glorious casting surprise which is far too spicy to waste here. The demonic producer of this ill-conceived cropper is a foul-mouthed craven joy called Les. Look closely at bald Les as he boogies around his office. It’s truly spooky.

15, 107 minutes

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