HAVANA (Reuters) - Hollywood came to Havana on Thursday as Cuban writers and artists gave an award to Benicio del Toro, star of the 2008 movie "Che," in a ceremony attended by fellow actors Bill Murray, Robert Duvall and James Caan.

Murray stole the show when he improvised a version of the song "As Time Goes By," then jokingly passed around a hat, asking for money.

Their presence lent a bit of Hollywood glitz to warming U.S.-Cuba relations, and may have been the precursor for the making of a film in Cuba.

A spokesman for the group said del Toro was in town for the award, but that Murray, Duvall and Caan were working on a "research project.

When asked if he and his pals might make a movie on the communist-led island, del Toro told reporters: "That depends on the governments, on the American government."

Because of the long-standing U.S. trade embargo against Cuba, Americans have been forbidden, with some exceptions, from visiting the island or doing most business there.

Hollywood stars such as Robert Redford, Arnold Schwarzenegger and director Steven Spielberg have come to Cuba in the past but cultural exchanges slowed due to restrictions imposed by former U.S. President George W. Bush.

The group's spokesman said they were traveling under a license granted by the U.S. Treasury Department.

U.S. President Barack Obama offered earlier this year to "recast" relations with Cuba, which have been sour since the 1959 revolution that put Fidel Castro in power.

Obama has lifted travel restrictions for Cuban Americans and restarted immigration talks with Cuba that were suspended under Bush.

Last week, the United States said a Bush-era news ticker on the U.S. Interests Section building in Havana, which the Cuban government viewed as an affront, had been turned off.

Puerto Rican-born del Toro won acclaim here last year for his portrayal of Ernesto "Che" Guevara, an Argentine who fought alongside Castro in the Cuban revolution, in the title role of the two-part biopic "Che," directed by American Steven Soderbergh.

The International Tomas Gutierrez Alea Prize, named for the late Cuban director who made the 1994 film "Strawberry and Chocolate," "makes me feel small and proud at the same time," del Toro said. "It's an honor to win this prize." Rosa Tania