Sprinter James Ellington will make his first competitive appearance since a serious motorbike accident at the Anniversary Games on Saturday.
The Briton has not run competitively since the accident in Tenerife in 2017.
But the 33-year-old, who suffered career-threatening injuries, will line up for the 100m at London Stadium.
"Believe it or not, I haven't run over 60m fast yet, which is mad. I'm not expecting to run anything fast," he told BBC World Service's Sportshour.
"But getting back on the track and just being able to complete the 100m will be another milestone.
"Then I can get back to the drawing board and focus on next year."
Before Tuesday's announcement, Ellington had hinted he would be taking part, re-posting a message on social media that he had "a dream I was running in the Olympic stadium again".
Ellington, who has won two European golds as part of Great Britain's 4x100m relay team, was out riding a motorbike with fellow sprinter Nigel Levine during a break from winter warm-weather training on Tenerife in January 2017 when he was hit by a car travelling in the opposite direction.
The damage was severe - a compound fracture of the right leg, a fractured left ankle, a fractured eye socket, a fractured sacroiliac joint and a displaced pelvis similar to what a mother suffers during childbirth.
Making a full recovery was one thing, but Ellington always had in mind that he would be back competing on the track again.
"I was thinking at the beginning that if I keep my leg, I will be back, and even if I don't keep my leg, I will still be back competing in the Paralympics.
"The experts were probably thinking I would not be able to walk properly again, let alone train and go on to running on the track again.
"But I had something different in mind."
I know this is crazy but in my mind Tokyo doesn't seem that hard now
That something is a place in the Team GB squad for the 2020 Olympic Games in Tokyo. It remains a way off but Ellington insists that is the easy part of his comeback.
"I know this is crazy but in my mind Tokyo doesn't seem that hard now," he revealed.
"I think the chances are high. I think I have gone through the hardest part so far, just being able to get back and train.
"As long as I can get rid of the residual pain that I am still getting in my pelvis which restricts my training, I don't see why I shouldn't be on that start line."
Ellington now has a carbon fibre rod in his right leg, while his pelvis is held together by nails and a metal plate.
It makes him a source of fascination at airport scanners, but he wasn't laughing when one of those nails inside his pelvis snapped when he was working out at the gym.
"I was coming up from a squat and there was a weird sound," he said. "It sounded like bubble wrap, cracking in my pelvis.
"I wondered what had happened but it felt like something went. The nail is still there now. It is broken inside me!"