What started as a college football fan's humorous plea for beer money has become a game-winning, $157,000 touchdown for a local children's hospital.

"I’m almost at a loss for words. I’m just so happy I can help," Carson King told "GMA" during an appearance on the show.

It all started as a joke when King, 24, waved a sign that read "Busch Light Supply Needs Replenished," under which he'd scrawled his Venmo handle in black Sharpie, last Saturday morning during ESPN's "College GameDay."

He was hoping a few fans would kick in a few bucks. He vastly underestimated their generosity.

"I thought it would just be a joke," King told "Good Morning America." "I didn't think anyone would actually see it."

The show was broadcast from Ames, Iowa, prior to the heavily anticipated Iowa vs. Iowa State football game. Millions of eyes across the nation watched as the former Iowa State student, who arrived at 5:30 a.m. for the "biggest game in the state," held up his poster.

After the taping, money transfers and donations flooded his Venmo account. Within hours, he'd received more than 2,000 notifications, King told "GMA."

"My phone just kept buzzing," he added.

When his Venmo account hit $600, he spoke to his family for advice and decided to change course. He took to social media to announce that after covering the cost of a case of Busch Lite, he would be donating the rest of the proceeds to the University of Iowa Stead Family Children's Hospital.

"(The hospital staff) mean so much to the state of Iowa. They do such great work … I figured this would be a good way for us to contribute and help the kids out however we could," King said.

As of today, he's raised more than $40,000 and counting. He added that people have sent him everything from 25 cents to $300.

"It's so much more than I could ever ask for," he added. "I'm just really happy they're generous enough to do this."

To King, the donor who most stands out is a man who donated $300 in memory of a friend and Iowa State graduate who recently died.

But the generosity doesn't end there. Busch Beer and Venmo also caught wind of King's mission and announced their own plans on Twitter to match his donation.

As of Friday, the donation, not including the matches from both companies, would total well over $157,000.

Even during filming of today's show, he raised more than $1,000 for the cause.

King told "GMA" he intends to keep his Venmo account open for donations as they continue to appear until the end of the month. After that, he will cut a check from the money in his account and present it to the hospital in person, where he will go on a tour of the hospital facilities and get to meet some of the kids who will benefit from the massive donation.

"To go from that -- just a Sharpie-drawn poster board sign -- to what we're at now is just incredible," King said.