The band with Bay Area roots broadcast a special performance on Facebook Live Tuesday afternoon and they're asking fans to donate to Americares.
"Americares is truly grateful to have Green Day's support," said Americares President and CEO Michael J. Nyenhuis. "Their generosity and dedication means so much to us, as we restore health and hope for those affected by Hurricane Harvey."
Green Day streamed a set from backstage at the MidFlorida Credit Union Amphitheatre in Tampa ahead of their performance there Tuesday night.
"We kept seeing these terrible images of devastation coming from Texas, and we knew we had to do something to help," said Green Day lead vocalist Billie Joe Armstrong. "We're encouraging fans to join us in support of Americares, a trusted organization that's on the ground providing aid."
Green Day has already donated $100,000 to join their effort.
An Americares emergency response team arrived in Texas just before the hurricane made landfall and immediately began working with federal, state agencies, local organizations and partner health clinics to meet urgent health needs.
Americares relief workers in Houston are delivering medicine and relief supplies to emergency shelters and supporting health facilities serving low-income and uninsured patients in affected areas.
Click here to watch Green Day's performance and click here to make a donation to Harvey relief efforts.