#FinishForMatt runner: 'He didn't get to finish the race. I had to finish it for him.'

Helen Wilkinson signed up for the London Marathon as a joke. But when her brother died unexpectedly, the 26.2-mile race became a mission in his honor. Courtesy of Helen Wilkinson

On April 23, Matt Campbell, a 29-year-old "MasterChef" semifinalist, collapsed at the 22.5 mile of the London Marathon. He died a day later. Today, Finish For Matt, an undertaking that began as a tribute to Campbell, has become a global movement. He had just 3.7 miles left to finish the marathon -- so now, people from Hong Kong to California are running the 3.7 miles on their own in honor of Campbell and raising money for charity.

The estimated stats say it all: more than 340,000 pounds raised. 65,000 miles (and counting) run. 55 countries -- including 40 U.S. states -- and 17,000 people involved, with more joining every day.

The effort all started when Matt Dorber, who also ran the London Marathon, decided last week to launch a Facebook page called Finish For Matt. He kept imagining the moment when Campbell's family looked at his tiny dot in the tracking app and saw that it wasn't moving. He wanted to pay a small tribute. He laid out three rules for participants: They had to run 3.7 miles, post a photo of their run with the hashtag FinishforMatt and donate whatever they could to Brathay Trust, the charity for which Campbell ran. Then, he was approached by a local newspaper journalist. A few days later, people representing the movement were running the 3.7 miles with Olympic runner Iwan Thomas on British television.

The tribute is still going strong with Facebook updates coming in regularly. A Norwich, England, participant walked the 3.7 miles on crutches and on one foot. He had lost his foot to bone cancer four years ago. A woman in Sacramento, California, found the Facebook page at random and was so moved by the gesture that she decided to run and donate. And Brit Helen Wilkinson felt she had no choice but to finish for Matt.

In 2016, Wilkinson had signed up for the London Marathon as a joke. Her brother Dan, 24, was a professional soccer player and was incredibly athletic. Meanwhile, she would give up halfway through a gym session saying, "I've done my part for today." The 30-year-old teacher signed up for the marathon to prove -- in a fun way -- she could run, too. She didn't think she'd actually go through with it. She'd never done anything beyond a five-kilometer run in her life.

That was before she got a phone call from her mother on Sept. 12, 2016. Her mother said that Dan collapsed while playing soccer. Wilkinson didn't realize it was serious. She thought, "Oh, he collapsed. Did he hurt his ankle?" It wasn't until she got to the hospital that she learned her brother had died. The cause of death was cardiac arrest.

Three weeks later, she got an email from London Marathon organizers. A spot was reserved for her in the 2018 race. She remembered telling her boyfriend, "Dan committed 110 percent to anything he ever did. It's going to take over my life training for this marathon, but I have to do it."

And the hard work paid off. She ran her first-ever marathon in 5 hours, 40 minutes. She said it felt cathartic. A big step in the healing process. Then, she heard about Matt Campbell. "This can't be happening," she thought.

"It seemed a little bit strange in a way that the reason I was doing it was because Dan had collapsed and died while playing football and, at the end of it, to hear that a guy, 29, had collapsed and died at the marathon. Somebody so fit and healthy. It just seemed shocking," she said.

Wilkinson came across #FinishForMatt on the London Marathon Facebook page. She knew she had to do it. Not long ago, just running the 3.7 miles would have been unthinkable. Now, just a week after she finished her marathon, on April 29, she ran the 3.7 miles in her hometown in Essex.

"I didn't see [Matt]. I didn't know him. But, I was in the race with him. He didn't get to finish it. I had to finish it for him. It was the only way," she said.