Director: Ben Stiller
Cast: Ben Stiller, Owen Wilson, Will Ferrell, Penelope Cruz
Certificate: 12

It was 1996 when Derek Zoolander was first introduced to the world at the VH1 Fashion Awards. 20 years later, he returns for his second big-screen outing and the joke is getting old. Ben Stiller's comedy creation was always based on a simple premise: a model who was really, really, ridiculously stupid, but also extremely good-looking.

For his feature-length debut, that straight-forward gag expanded into a satire of the shallow fashion industry, with the so-hot-but-still-not-with-it Hansel (Owen Wilson) teaming up with Derek to thwart the plan of malicious designer Mugatu (Will Ferrell), who wanted to kill the Malaysian Prime Minister. Now, Zoolander's a has-been - his infamous centre for teaching kids to read was built out of the same materials as the tiny cardboard model in the first film and collapsed, killing his wife and estrangnig him from his son - but even more people want a piece of him.

That's true of new, so-inaudible-right-now designer Alexanya Atoz (Kristen Wiig), who invites him to headline her show, but it's also true of the real fashion industry, with everyone from Anna Wintour to Tommy Hilfiger queing up for guest appearances. One climactic scene sees half of the world's biggest names standing in the same room, each one competing to see who can be the worst at reciting bad dialogue. Not only it is hard to tell who the joke's on any more, but it's also hard to tell where the jokes are, period: the film has more celebrity cameos than laughs. By an alarming distance.

The cast are clearly still enjoying themselves, but the same cannot be said of us: the script, co-written by Justin Theroux, Stiller, Nicholas Stoller and John Hamburg, falls flat on the runway at almost every opportunity. Stiller's delivery of deliberately dumb things is present and correct, but it's something we've seen countless times before. Even that, though, is inconsistent: one scene sees him explain an insult to Hansel, a moment so completely out of character that you wonder if the writers have been taking crazy pills, or simply forgotten what made Zoolander entertaining to begin with.

The addition of Penelope Cruz to the ensemble could inject some novel humour, but even she is lumbered with material that feels old-hat, mostly relying upon her ample breasts. The return of Ferrell, meanwhile, raises a smirk, but feels curiously lazy - the uneven screenplay can't even decide whether his nefarious plot is real or not.

There are glimpses of wit, such as an opening sequence that introduces Justin Bieber - then swiftly un-introduces him. It's a wonderfully over-the-top prologue that raises the question of whether Derek's signature look is the predecessor of the youth of today's preening obsession with duck-faced selfies. That train of thought, though, is swiftly cast aside in favour of walk-on roles from Billy Zane, Katy Perry and MC Hammer. The only guest star that draws the odd giggle is Kiefer Sutherland, who relishes the chance to send himself up. The rest feel forced, not least the brief appearance of Benedict Cumberbatch as a trans model, All, who may be a well-intentioned nod towards the modern fashion world but winds up so clumsily depicted (is she the butt of the joke, or is Derek?) that Cumberbatch's scenes are merely awkward.

It's not impossible for Derek Zoolander to be funny in 2016: earlier this year, he starred in a video by Vogue that saw him answering 73 questions during a tour of his home. It was short, sharp and frequently amusing. This sequel is bloated, messy and dull. Perhaps, after his one movie, Zoolander is a character best kept to web series and short skits, a la Alan Partridge's Mid Morning Matters? Either way, Zoolander 2 is a big step down in form for both Derek and Stiller. The only thing that remains consistent is the excellent costume design, which goes from the slick to the supremely ridiculous at the drop of an oversized fur coat. But watching Zoolander to admire the clothes is like watching Dr. Strangelove for the nuclear warhead; it's missing the point, which is to be funny. This isn't. Zoolander 2 is really, really, ridiculously disappointing.