BOSTON — Elizabeth Warren may be running for the United States Senate in Massachusetts, but her campaign is getting deep support 3,000 miles away in California, where the other day, Cher was speaking glowingly of Ms. Warren’s candidacy.

“She makes an unbelievable impression,” Cher said in an interview from Malibu, explaining that she had become a fan after watching some of Ms. Warren’s speeches about economic injustice on YouTube. “I’m just thrilled every time I can hear the woman speak.”

Nearly 20 percent of Ms. Warren’s itemized donations (those over $200) in the last quarter of 2011 came from California, where a number of actors and others in the entertainment industry are fired up about her race against a first-term senator, Scott P. Brown, to reclaim for Democrats the seat long held by Edward M. Kennedy.

And Mr. Brown is seeking to use their enthusiasm against her.

Last Wednesday — the day before Skip Brittenham, an entertainment lawyer, and Heather Thomas, an actress, held a $500- to-$5,000-per-ticket fund-raiser for Ms. Warren at their home in Santa Monica — the Massachusetts Republican Party released a Web video in the style of an old movie trailer, with an announcer proclaiming, “Hollywood has a new ‘It Girl’ — Hollywood has fallen for Elizabeth Warren big-time.”