Sacha Baron Cohen stars in “Bruno,” his much anticipated follow-up to “Borat.”

LOS ANGELES — The problem with "Bruno" is Bruno himself. Compared to Borat — and it's impossible to avoid the comparison — there simply isn't enough to the character to build an entire feature-length film around him.

Both spring from the brash and creative mind of British comic Sacha Baron Cohen, who unleashed them upon the world through his sketch comedy program "Da Ali G Show." Borat, the bumbling journalist at the center of the 2006 smash "Borat: Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan," provided a prism through which to explore people's prejudices, hypocrisies and foibles. Sure, Baron Cohen frequently shot fish in a barrel, but as Borat traveled across the United States trying to understand what makes us tick, the uncomfortable discoveries he made seemed endless. More importantly, for a comedy, they were usually funny.

Bruno is a one-joke character in a one-joke movie, and it's a joke Baron Cohen beats into the ground. He's a flamboyantly gay Austrian fashion correspondent who repeatedly shocks people with his flamboyant gayness. The end.

In small doses — on the TV show and at the film's high-energy start — he can be a hoot. Here, big laughs come intermittently, and the longer "Bruno" drags on, the more apparent it becomes that there's nothing to him. He's as vapid as the celebrity culture he's stridently spoofing — which makes it hard to care about him.

Another fundamental flaw in "Bruno" is that it's much more obvious which gags are staged and which are truly spontaneous. Much of the fun in "Borat" came from watching the unpredictability of Baron Cohen's interactions with regular people, holding our collective breath to see how his unsuspecting victims would react to the awkward and politically incorrect things he did and said. While the structure and intentions of "Bruno" are nearly identical — both films come from director Larry Charles, with Baron Cohen among a team of writers — the supposedly daring moments play out a little too neatly.

What seemed likely when "Bruno" was announced appears to have happened: Baron Cohen is simply too famous to go undercover with his preferred modus operandi.

As the movie begins, Bruno is the host of the Austrian style and pop culture program "Funkyzeit." He determines what's in and what's out, schmoozes with celebs and parades around in a wild array of butt-hugging outfits. But after he crashes the stage of a Milan fashion show, he's banished from this glittering world. Naturally, he decides to reinvent himself as a superstar in the United States.

You have to give Baron Cohen credit for keeping a straight face regardless of the silly situation. But at the end, the cameos in a "We Are the World"-style anthem from Elton John, Bono, Snoop Dogg and others confirm what you may have suspected all along: Baron Cohen has become part of the very establishment he's parodying.

TITLE: “Bruno”CAST: Sacha Baron Cohen, Gustaf HammarstenDIRECTOR: Larry CharlesRATED: R for pervasive strong and crude sexual content, graphic nudity and languageGRADE: * ½ (out of 4)