Genaro Molina via Getty Images Bernie Sanders spoke at a rally for University of California workers in March. This week his presidential campaign urged supporters to join the picket lines.

Thousands of workers from the University of California waged a one-day strike Thursday and found some unexpected allies out on their picket lines.

In an unusual move for a presidential candidate, the campaign of Sen. Bernie Sanders (I-Vt.) sent out targeted text messages and emails to its supporters in California a day ahead of the strike, urging them to join workers as they rallied against the university system in a labor dispute.

“Tens of thousands of workers in the University of California system are standing up this Thursday to stop the outsourcing and privatization of union jobs,” the email said. “We are hoping you can join these workers tomorrow.”

The note included an RSVP link and an address for a local picket.

The move apparently worked, according to John de los Angeles, a spokesperson for the American Federation of State, County and Municipal Employees Local 3299, one of the unions involved in the strike.

“I deployed a press team across the state and was in contact with them,” de los Angeles said. “They were sending me pictures of random supporters out on the line because they had received an email or text from the Bernie campaign. That happened all over the place.”

It’s not uncommon for a presidential candidate to get out on a picket line to show support for workers. Julián Castro, another Democratic presidential hopeful, rallied with the California workers on Thursday. And when grocery store employees went on strike in New England, several candidates either visited pickets or gave speeches to the crowds.

But it’s far more novel to use a campaign’s infrastructure in an effort to help workers in a dispute with their boss. Fervent Sanders supporters point to this type of maneuver when they claim they are trying to build a movement, not just a candidacy.