Sally Pearson, Australia's face of the Commonwealth Games, has withdrawn from Gold Coast 2018 because of injury.
The 31-year-old 100m hurdler, regarded as one of the hosts' gold-medal prospects, had been struggling with an Achilles problem.
Announcing her withdrawal, Pearson said she was "gutted, absolutely gutted, tears flowing, almost like grief with a numbness phase and a crying phase".
She added: "Not being able to run for Australia is gut-wrenching."
The Gold Coast native featured in the Games' opening ceremony on Wednesday.
Speaking at a news conference on Thursday, she said the decision to pull out was made a couple of days ago, when the injury flared up.
But she wanted to delay the announcement until after the opening ceremony, during which she carried the Queen's baton in the Carrara Stadium.
"I had a big role to play in the opening ceremony which is why I waited until today to make the announcement," said the 2012 Olympic champion.
"I did everything I possibly could. I left no stone unturned to run in the 100m hurdles and the 4x100m relay."
The two-time world champion was composed throughout the news conference, and was aware some fans may feel let down.
"know I have a lot of fans who were wanting to watch me race. But for me, it is about my health and I want to go to Tokyo (Olympics) in 2020."
She said retirement was not on her mind and her focus was to be fully fit for the Olympic Games.
"This is not over for me," she said, adding that running in Tokyo was the "dream I hold on to, to finish my career the best way possible".