Sacha Baron Cohen has reportedly been barred from the Oscars because of plans to come dressed as a Middle Eastern despot.
The actor had vowed to walk the red carpet before the ceremony as the protagonist from his new film, the Dictator.
But according to industry website Deadline, the Academy has vetoed the idea and promised to remove his ticket allocation, unless he changes his mind.
A spokesperson for the Academy denied that any decision had been taken yet. But they said: "We would hope that every studio knows that this is a bad idea. The Red Carpet is not about stunting."
A Paramount spokesman said: "Unless they're assured that nothing entertaining is going to happen on the Red Carpet, the Academy is not admitting him."
Mr Baron Cohen, 40, is due at the ceremony because the Martin Scorsese film Hugo, in which he played a train conductor, has been nominated.
Five years ago he refused to present an award at the ceremony after the organisers blocked his plan to come dressed as Borat.
The 84th Academy Awards takes place this Sunday in Los Angeles, hosted by Jewish actor Billy Crystal. The silent film homage The Artist is expected to sweep the awards, as it did at the recent Bafta ceremony, although films by Steven Spielberg and Aaron Sorkin have also been nominated.
