Trump, Clinton or Sanders? Celebs pick sides in US elections

Hillary Clinton has Ben Affleck and George Clooney on her team, while Donald Trump's celebrity backers fall more on the tough guy side with the likes of Hulk Hogan or Mike Tyson.

Susan Sarandon and Spike Lee are feeling the Bern.

Celebrities have long had an active voice in promoting their favorite candidates during America's presidential elections and this year is no different.

Hardly a week goes by without a Hollywood star, a studio mogul or a celebrity throwing a lavish fundraiser for their favorite politician or party, where plunking down $50,000 to schmooze with a candidate is common.

"The main importance of Hollywood celebrities is that they draw attention to a candidate in a way no other industry can," said Steve Ross, a history professor at the University of California.

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Consider talk show host Oprah Winfrey's endorsement of Barack Obama during the 2008 Democratic presidential primary, which brought him about one million votes, according to a study by the University of Maryland.

Of the candidates hoping for a similar windfall this year, Clinton -- the Democratic frontrunner, battling rival Bernie Sanders -- appears the favorite among Hollywood's movers and shakers.

Apart from Clooney and Affleck, she has also won endorsements from director Steven Spielberg, singers Barbra Streisand and Sting and a slew of other A-listers who together represent the fifth largest source of contribution for the former secretary of state.

Actress Susan Sarandon arrives at the Time 100 gala celebrating the magazine's naming of the 100 most influential people in the world for the past year in New York April 29, 2014. (Reuters)

Sanders has also attracted a stable of celebrity backers such as actor Mark Ruffalo and director Michael Moore.

Trump, now the presumptive Republican nominee -- and himself something of a celebrity -- is so far trailing with a relative B-list of big names behind him, many of them from the world of sports.

Overall, celebrities have so far poured $27 million into the 2016 election cycle, with almost three-quarters of the money going to Democratic hopefuls, according to the Center for Responsive Politics, a Washington-based research group.