The biggest thing to happen at the Nebraska Cornhuskers' spring football game Saturday was the smallest person on the field, a 7-year-old boy with brain cancer.

That boy, Jack Hoffman, ran 69 yards during the game's fourth quarter to score the scrimmage's final touchdown and become the game's leading rusher.

Jack, of Atkinson, Neb., was diagnosed with brain cancer in April 2011 and is undergoing a 60-week chemotherapy program. Now on a two-week break from the treatment, Jack and his family received a call from the University of Nebraska's athletic department inviting them to Saturday's game at Memorial Stadium for a special play.

"This was kind of an impromptu idea by the University of Nebraska football staff and they just wanted to provide a once-in-a-lifetime opportunity for Jack," his dad, Andy Hoffman, said today on " Good Morning America."

Wearing a mini-Cornhusker uniform with the No. 22 of his idol, star Nebraska running back Rex Burkhead, Jack took the field before more than 60,000 fans at Memorial Stadium.

The mini-me, instant football star emerged from a huddle with players nearly triple his size and lined up for the play after a little direction from his new teammates. He took a handoff from quarterback Taylor Martinez and then ran clear down the field and into the end zone.

As the referee lifted his arms in the touchdown sign, Jack was mobbed by players from both sidelines and lifted on the shoulders of Nebraska's star players.

"Yeah, absolutely," Jack said on "GMA" when asked if his touchdown run was as fun as it looked.

Jack is a lifelong Cornhusker fan who went to his first game on his fifth birthday. Just before his second brain surgery, in September 2011, his family reached out to the university and arranged for Jack to meet Burkhead and tour the stadium of the team he so loves, according to the family's foundation's website.

That meeting turned into a friendship with Burkhead that continues to this day. Burkhead wears a wristband that says, "Team Jack-Pray," and is also a major supporter of the foundation started by the Hoffman family to fund pediatric brain cancer research, the Team Jack Foundation.

Jack's touchdown run that came from his initial meeting with Burkhead has now garnered even more attention for the family and their foundation. It was the number one "Play of the Day" video on ESPN and has been viewed more than two million times on YouTube.

"We just kind of thought we were going to go down there and do that [the touchdown play]," said Hoffman. "Little did we know that when we signed up for that it was going to turn into this big national story so it's kind of overwhelming, actually, for our family."