The saccharine conventions of show business were thrown out of the window last week, when the Hollywood actress Maria Conchita Alonso was collared by paparazzi and asked if she was pleased about her former co-star Sean Penn's recent Oscar victory.

"He's an amazing actor. I can't take that away from him," she said of Penn, who worked with her on Dennis Hopper's the 1988 cop film Colors, with a cynical shake of her head. "It's just that he has no clue at all what's going on in Venezuela.

He's been praising Hugo Chavez, who is a dictator and a killer. He should just shut up about what he doesn't know."

Alonso, who was born raised in Venezuela, was apparently upset by a glowing article that Penn had written for The Nation magazine about her homeland's charismatic but increasingly dictatorial left-wing President.

In normal circumstances, Alonso's interview might have been brushed under the carpet. But for the first time a Hollywood insider was saying what much of America thinks: left-wing luvvies in the movie business should wake up to the real nature of their hero. For one thing, Chavez throughout his career has criticised Hollywood as a medium of American "cultural imperialism". And Penn, who since his Oscar-winning performance in Milk has become a vociferous gay rights activist, is also open to allegations of hypocrisy. The Venezuelan leader's political hero, Fidel Castro,imprisoned and executed gay men, and once declared approvingly: "In this country [Cuba] there are no homosexuals."

Penn has plenty of company. On Thursday, Benicio del Toro made headlines when he took tea with Chavez at his palace in Caracas. The actor, in Venezuela to promote Steven Soderbergh's film Che, told journalists that his host was "nice" and that he'd "had a good time". Del Toro's comments caused apoplexy on the political right in the US, which has long considered the Venezuelan public enemy number one, but lately even Democrats have been perturbed by his Chavez's intolerance of media criticism and political opposition.

Last month, by way of through a referendum, Chavez managed to alter the constitution to allow him to run for as many terms of office as he likes.