Oprah Winfrey has been a dedicated supporter of the innovative Ron Clark Academy from the beginning, propelling its co-founder to fame when Clark visited her daytime talk show years ago.

She's also supported the school financially over the years and on Friday, at the school's 10th anniversary celebration, she had a very special birthday gift: a $5 million donation.

Clark was knocked over by the gift - literally! Here's a video clip of him keeling over in delight after the surprise announcement:

The evening included remarks from Mayor Kasim Reed, who quipped that he was missing the Atlanta Hawks' ceremonial retirement of a jersey in his honor to attend the event, performances from the hit Broadway phenomenon "Hamilton" and inspiring moments highlighting the school's students.

Winfrey kicked things off in trademark style, explaining her love for the school before announcing her latest financial gift.

"I love this school!" Winfrey told the cheering crowd as she took the stage. "It's hard to believe it's been 10 years. I was here for the first graduation. I wanted to be here to actually mark this moment in time. What it takes to build a school over 10 years, I know."

The Oprah Winfrey Leadership Academy for Girls, a boarding school in South Africa, also opened 10 years ago. She talked about her love for its students, who she calls her "daughter girls," when she spoke at Agnes Scott College's graduation this spring.

At Friday's event, Winfrey talked about how important her own teachers were, beginning with a particularly impactful fourth grade teacher. Clark caught her eye in the year 2000, when he was named the Disney American Teacher of the Year. He visited her show a few years later, to promote his book "The Essential 55."

With her powerful endorsement, the book became a best-seller. He used the resulting proceeds to fund the purchase of an old factory that became the Ron Clark Academy.

"I've never known another human being with such drive, such courage, such passion, in the face of everybody going.. what? You are a true guiding light for so many," Winfrey said. "What I love about you, the reason I say yes every darn time, you are doing what you are meant to be doing. You didn't just answer your call, you answered God's call. Most people are deaf, they don't hear it. Ron heard it and answered the call."

Here are some photos she posted:

And here are some more photos from the event: