Geneva: A fundraiser headlined by Hollywood personality George Clooney raised hundreds of thousands of dollars for US presidential candidate Barack Obama.

The gala held for Americans in Geneva was the actor and director's first public appearance to back Obama.

Some 170 contributors paid $1,000 each to hear him speak at a cocktail party held at a museum in Geneva's Old Town, while 75 others spent $10,000 per head to attend a dinner with the star at the organiser's apartment, Clooney's lawyer said.

Clooney, who is also an active humanitarian, charmed the audience with a stirring speech, some attendees said.

The “twin events'' could raise more than $900,000 for the Democratic presidential campaign ahead of the November 4 election.

The 57-year-old star came fresh off the world premiere of the Coen brothers' comedy Burn After Reading in Venice.