Franklin was the secret celebrity guest. There's just one problem: "I'm not a celebrity!" she exclaimed.
Franklin was worried the kids might be disappointed.
"What if they are expecting Brad Pitt or Taylor Swift, and I come walking in?" she said.
But that was not an issue at all.
"Oh my gosh!" 16-year-old Michaela Rael beamed. "I'm such an enormous fan. You have no idea!"
The smile on Rael's face was enormous. This was from the young lady who was in too much pain to have a visitor just an hour before.
"It had been my hardest day yet," Rael said.
The staff at The Children's Hospital in Aurora knew the five-time Olympian would be a thrilling visitor.
Franklin flashed her million watt smile and grabbed a 10-year-old cancer patient's hand.
"You are beautiful," she said to Cynthia Lozano.
Cynthia lost all her hair during chemotherapy. It was clear this day means as much to the Olympic Gold medalist as it did to the children.
"You walk into their rooms and it's so easy to see God on their faces," Franklin said. "You can tell they have been through so much and still push through."
She said it should be an inspiration to everyone.
Missy Franklin came straight from school to The Children's Hospital in Aurora. She is a senior at Regis Jesuit High School. She's studying for her winter finals next week.
She spent an hour and half on two different floors. Franklin visited children who are too sick to go into the public areas in the hospital.
Makenna Wallin, 15, was diagnosed with cancer two days ago. She is a swimmer too.
"You do the butterfly?" Missy asked. "I am seriously impressed. I can't do that stroke."
Her coach, Todd Schmitz, laughed. "She's not kidding," he said.
He cancelled practice so there would be time for the hospital visit.
Missy Franklin stepped off a plane from London four months ago. She was the first woman to qualify for seven events at the Olympics. She set two world records and three American records. She won five medals; four of them gold.
"I still think these medals aren't real," she laughed. "I expect that I'll look down and they'll be made of chocolate or something."
Even with a rigorous training schedule, traveling to meets, and a full class load at school, Franklin makes as much time as she can to connect in her Colorado community and beyond. It is sincerely important to her.
"These patients have such an impact on me," Franklin said. "They are all amazing."
After visiting with each patient and taking pictures with nurses and doctors, Franklin headed down to the hospital atrium . A crowd of patients and their families were waiting. She and her STARS teammates danced with the kids.
They hoped that this time would make some concerns and hurts fade, at least for awhile.