On Sunday evening, as the full, terrifying scope of Hurricane Harvey’s devastation began to set in, Houston Texans star J.J. Watt took to Twitter and made a simple request: let’s raise some money to help.

Watt set an initial goal of $200,000, which was surpassed in less than two hours. And so Watt kept raising the goal, and fans and celebrities have kept responding.

On Thursday morning, Watt was on Twitter again, this time to announce that the fund he set up had reached a major milestone: $10 million. On Thursday evening Watt announced donations had reached $12 million.

“Absolutely incredible,” Watt wrote. “The most difficult times bring out the best in humanity.”

“I cannot thank everybody enough,” Watt said in a video announcing donations had reached $10 million. “We have semi trucks being filled up as we speak; that’s phase one. We have things like water, food, generators, baby supplies, cleaning supplies… Houston, we’re thinking of you.”

More than 100,000 people donated in less than four full days since Watt first asked for donations.

On Wednesday, Ellen Degeneres announced on her talk show that she, with help from Walmart, were chipping in $1 million; Amy Adams Strunk, owner of one of the Texans’ divisional rivals, the Tennessee Titans, also gave $1 million.