Sen. Bernie Sanders, I-Vt., two days before Super Tuesday, held two massive rallies on Sunday in delegate-rich California, drumming up enthusiasm before a combined crowd of nearly 25,000 people, the campaign estimated.

More than a third of all delegates are on the line Tuesday, with 14 states and American Samoa holding primaries. Of the roughly 1,350 delegates up for grabs, 415 are from California, which is why Sanders’ campaign is hoping left-wing enthusiasm there can carry them to a big win.

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 "Our campaign has built a multiracial, multigenerational working-class movement across California," said Rafael Návar, the campaign’s California state director, in announcing the crowd count. "Our supporters and our volunteers across the state are what drives this campaign, and we have the energy and excitement to do very well here in California." 

Sanders’ rallies were huge even by his standards and certainly compared with crowds for other candidates. Sen. Elizabeth Warren, for instance, rallied a crowd estimated at 2,000 in Houston a day earlier.

Sanders has been hitting the Golden State hard ahead of this week’s primaries. A campaign press release stated that volunteers made more than 6.5 million phone calls and knocked on more than a million doors. 

The democratic socialist was the clear front-runner for the Democratic nomination after early contests in Iowa, New Hampshire, and Nevada, but former vice president Joe Biden showed he is still in the mix by soundly defeating Sanders in South Carolina over the weekend.

Sanders currently leads Biden by eight delegates heading into Super Tuesday, and former New York City Mayor Mike Bloomberg will appear on ballots for the first time this week after pouring hundreds of millions of dollars into his campaign. 

Sanders' first rally Sunday was held in San Jose. 

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But Sanders' star-studded second rally in Los Angeles also sparked controversy in the hip hop world when rapper and Public Enemy member Chuck D’s planned performance led to a rift between the group and founding member Flavor Flav. After Flav’s lawyer sent a cease-and-desist letter accusing the Sanders campaign of using his likeness and trademarked oversized clock at the rally even though he "has not endorsed any political candidate in this election cycle," the group announced they and Public Enemy Radio are "moving forward" without him. 

Aside from Public Enemy Radio, several other celebrities participated in the event, including Dick Van Dyke and Sarah Silverman.

Fox News’ David Aaro and Andrew Craft contributed to this report.