According to a press release from the Red Cross, the actress is a longtime supporter of the organization and made her donation Monday.
Jessica, a volunteer with the Red Cross answering phones at the Telethon for Texas phone bank said, "I mean, I think in a lot of ways we in Florida know first hand the experience that can come from tropical weather and it's important we stand with our neighbors".
"Most of the volunteers we've sent down there right now primarily are trained in what we call 'mass care and sheltering, '" Sanders says.
Officials are trying to ramp up blood donations to not only fill shelves for local needs during what they expect to be a busy Labor Day weekend, but also in anticipation of making some blood supplies available to hurricane-stricken areas. There have been at least 19 confirmed flood-related deaths and there are reportedly 30-40 people still unaccounted for. They are also accepting new or gently used clothing for adults and children.
Elizabeth Penniman, vice president of communications for the Red Cross, said in a statement to CNN that the organization is "thankful for the overwhelming and generous response from those who want to help those affected by this devastating storm".
So far, more than 35,000 people have sought refuge at Red Cross and partner shelters following "catastrophic" flooding in Texas. "We're grateful and humbled by the outpouring of support from our viewers".
Bullock is the latest in a long list of celebrities who have donated to the relief effort, including Houstonian Beyonce. She gave the same amount to the organization in 2004 after a tsunami in Indonesia and again in 2005, following Hurricane Katrina in New Orleans.
If you tried helping Harvey relief efforts by texting the American Red Cross to donate, you might have received an unexpected message back.
CNN has reached out to a rep for Bullock for further comment.