Hollywood actors Susan Sarandon, Shailene Woodley and Danny Glover joined more than 1,000 demonstrators at a rally in the Germantown neighborhood of Philadelphia ahead of the Democratic National Convention on Sunday to reaffirm their commitment to Vermont Sen. Bernie Sanders’ progressive campaign causes, with a focus on climate change issues.

The trio of stars — staunch supporters of Sanders in the Democratic presidential primary earlier this year — were on hand to deliver speeches and to take in a screening of the climate change documentary How to Let Go of the World and Love All the Things Climate Can’t Change from director Josh Fox, perhaps best known for his fracking documentary Gasland.

In an interview with The Young Turks at the rally, Sarandon said that the purpose of the event was to show their fellow Democrats that progressive Sanders supporters are “still here,” and that “Bernie has ignited a spark and we’re not letting that go.”

“It’s important to know that this army is going to continue, and we’re not resting on anything on this election,” Sarandon told TYT.

When asked about the leaks of thousands of emails from the DNC earlier this week that appeared to show the Democratic Party actively colluding to suppress Sanders’s campaign, Sarandon called the situation “disgusting.”

“Nixon resigned when they broke into the headquarters,” Sarandon said. “And now you find all this tampering going on, and I know there are lawsuits and things. I think we really have to ask what’s happened to us, in terms of what we’re willing to sacrifice to get our person in. What does it really say about us if this goes by unattended?”

Sarandon was an early supporter of Sanders’s presidential campaign, and made waves in Hollywood with her support for the democratic socialist earlier this year. In March, the 69-year-old Thelma and Louise star suggested that Donald Trump would be a better president than presumptive Democrat nominee Hillary Clinton.

Woodley, best known for her role in the Divergent film franchise, has also been an outspoken Sanders supporter. In May, the 24-year-old actress joined fellow actors Rosario Dawson and Kendrick Sampson on a get-out-the-vote RV road trip across the Golden State to rally supporters to the Vermont senator’s campaign ahead of the state’s primary.

“If you show up with love and solidarity to those around you, that sparks great change,” the actress told attendees at Sunday’s rally, according to the Associated Press.

Sarandon, Woodley and Glover are just a few of the stars descending on Philadelphia this week, though most will be found joining in on the proceedings at the DNC. Lady Gaga and Lenny Kravitz are expected to headline a concert Thursday just hours before Clinton formally accepts the Democratic presidential nomination, while actresses Lena Dunham, Eva Longoria and America Ferrera and singers Demi Lovato and Katy Perry are all expected to speak or participate in events throughout the week.

Follow Daniel Nussbaum on Twitter: @dznussbaum