WATCH: “That’s my dad!”: Gus Walz tearfully cheers on his father as he accepts Democratic VP nomination

Gus Walz sat in the front row for the biggest moment of his father’s life, and the 17-year-old couldn’t and didn’t hold back his emotion.

“That’s my dad!” Guz Walz yelled from the crowd as Tim Walz accepted the Democratic nomination for Vice President.

He stood, tears streaming down his face, and pointed to his father, who was giving a speech to thousands of people in a packed arena and millions more watching at home.

The teen’s exuberance captured hearts and went viral, becoming perhaps the defining image of his father’s address and further humanizing a running mate picked by Vice President Kamala Harris in no small part for his everyman appeal.

Gus wept through much of his father’s speech, and when it was over, climbed on stage with his family and wrapped his dad in a tight bear hug, burying his face in his shoulder.

Gus is a high school senior. His parents recently disclosed to People magazine he has a non-verbal learning disorder, ADHD and an anxiety disorder. But they called his condition “his secret power” and said he’s “brilliant” and poised for success. He got his driver’s license last fall.

When Tim Walz was elected governor, Gus cheered because it meant he could get a dog. They adopted a black lab named Scout a few months later.

Gus Walz is getting his own turn in the spotlight after his older sister, 23-year-old Hope Walz, delighted Americans with the playful social media videos she filmed with their dad.

Tim Walz talks often about the fertility treatments his wife, Gwen, underwent to get pregnant with Hope, a journey he says inspired her name. As he told the story Wednesday, Hope made a heart with her hands and held it over her chest.

“Gwen,” Walz said to his wife, “you are my entire world and I love you.”