NFL star Travis Kelce is teaming up with activist investor Jana Partners and other executives in a bold bid to revive Six Flags Entertainment, the struggling amusement park chain.

The group, which also includes Glenn Murphy and Dave Habiger, has built a 9% ownership stake in Six Flags — making it one of the company’s largest shareholders. Jana Partners said Tuesday it plans to “engage” with Six Flags’ management and board to explore ways to boost shareholder value and improve the overall guest experience.

News of the investment sent Six Flags shares soaring nearly 18%, with another 5% rise in after-hours trading. Still, the company’s stock remains down about 47% this year. Six Flags recently reported a $319.4 million loss for the first half of the year, citing poor weather and weakened consumer spending as key factors behind a 9% drop in attendance during the last quarter.

Kelce, known for his high-energy performances on and off the field, said the partnership is deeply personal.

“The chance to help make Six Flags special for the next generation is one I couldn’t pass up,” he said.

The investor group’s move signals growing pressure on Six Flags’ leadership to turn around the iconic theme park brand and bring back its thrill for families nationwide.