Minnesota Gov. Tim Walz formally accepted the Democratic nomination for vice president Wednesday night in Chicago. And as he did, the former congressman and teacher gave a nod to his wife, Gwen, daughter, Hope, and his son, Gus.

"You are my entire world and I love you," Tim Walz said.

A teary-eyed Hope responded by making a heart gesture toward her father. Gus began to clap as he cried, stood up and mouthed the words, "That's my dad!"

The moment took social media by storm and capped a night that featured a performance of Prince's "Let's Go Crazy" by John Legend and Sheila E. and a brief appearance from Mankato West High School alumni who played football while Walz was a geography teacher and coach there.

Hundreds packed the school gymnasium in Mankato to watch the event.

Who is Gus Walz?

Gus, 17, is the younger of the Walz children. Hope, 23, was so named because she was born after the couple's long struggle with infertility.

The Walz family opened up to People magazine in August, sharing that Gus has a non-verbal learning disorder, as well as ADHD and anxiety. The Walzes said that as Gus grew up, they noticed he was different from his classmates and preferred to spend time alone.

"When he was becoming a teenager, we learned that Gus has a non-verbal learning disorder in addition to an anxiety disorder and ADHD, conditions that millions of Americans also have," the Walzes told People, adding that their son's "condition is not a setback — it's his secret power."