South Africa's Oscar Pistorius is the biggest star in Paralympic sport after winning three gold medals in Beijing four years ago and going on to compete at the Olympic Games last month.
He returns to London targeting four gold medals at the Paralympics, but has the sprinter's Olympic journey harmed his Paralympic chances?
Allison Curbishley, former Great Britain 400m runner and 5 live Paralympics analyst, examines the 25-year-old's chances of matching - or improving upon - his achievements in Beijing.
The Pistorius story
Oscar Pistorius was born without fibulas in his legs and had the limbs amputated below the knee when he was 11 months old. The carbon fibre artificial legs he uses have led to his nickname of the 'Blade Runner'.
His first international competition against able-bodied athletes came in 2007, but later that year athletics' governing body, the IAAF, banned the use of any equipment that provided "the user with an advantage over another athlete".
In 2008, Pistorius won his battle with the IAAF to compete against able-bodied athletes, but he failed to qualify for the South African Olympic team in Beijing.
He was selected for the 2011 World Athletics Championships in Daegu, reaching the individual 400m semi-finals and winning a silver medal in the 4x400m relay, although controversially he did not run in the final.
There were further doubts this year that he would get his chance to run in the Olympics when the South African Sports Confederation and Olympic Committee (Sascoc) warned they would "not take passengers to London" .
But despite failing to reach the qualifying 'A' standard for a second time in 2012, Sascoc still gave him the green light for London.
Pistorius at the London Olympics
Pistorius made history by becoming the first double leg amputee to participate in the Olympics when he took to the track for the 400m in London last month. He went on to reach the semi-finals in the individual event and the final of the 4x400m.
He was also chosen to carry the South African flag for the closing ceremony.
"It has been a great achievement for me to come here and compete," he said.
"I never set out to prove a point, but I do feel I have made the point. It's been a privilege to be on the track with all the other phenomenal athletes."
Pistorius at the Paralympics
Pistorius first competed at a Paralympics in Athens eight years ago as a "curly-haired kid" aged 17, taking bronze in the 100m and winning the 200m with a world record of 21.97 seconds. Records tumbled in the years that followed and in Beijing he won gold in the 100m, 200m and 400m.
In London he will compete in four events - the T44 100m, 200m, 400m and 4x100m.The 'T' represents a track event; classes 40-46 are for athletes with an impairment that affects their arms or legs, including amputees.
Curbishley: "In 2012, Oscar has been concentrating on the 400m in his bid to race both at the Olympics and the Paralympics.
"It will be interesting to see how much a lot of racing over 400m will impact on his 100m and 200m events.
"It could be to the detriment of his 100m, because the 200m and 400m balance each other well, and I wouldn't be surprised if this was the last time we saw him running over 100m."
The 100m showdown
In the same way that Usain Bolt captured the imagination at the Olympics, Pistorius does the same in the Paralympic athletic events - and the 100m should be one of the highlights of the Games.
He might be the defending champion but, unlike Usain Bolt, the South African is not the favourite for the shortest sprint.
"I think it's important to remember that Yohan Blake and Bolt are both 100m runners - I'm a 400m runner running in a different event," Pistorius said this week.
Americans Jerome Singleton and Blake Leeper, Britain's Jonnie Peacock and Pistorius's fellow South African - and Paralympic room-mate - Arnu Fourie are among a number of potential winners.
Curbishley: "He could miss out on a medal in the 100m because the strength in depth over that event and the 200m has got a lot stronger since Beijing.
"You now have athletes like Peacock and Leeper breaking the 11-second mark, which Oscar hasn't done since 2008, plus the likes of Fourie and Singleton also challenging.
"It's fantastic for athletics fans, because we are going to see a phenomenal 100m with people going head-to-head with Oscar, who will be under pressure."
"We know his start is his let-down and he takes a while to get out of the blocks, and his pick-up isn't as fast as a single-leg amputee, which puts him at a disadvantage over the shorter distance.
"But his strength as an athlete is his leg turnover. He is built to be a 400m runner where his speed endurance comes to the fore."
The T44 100m final takes place at 21:16 on Thursday, 6 September.
How many medals will he win?
With Pistorius himself saying of the 100m, "If I can just get in the top three I think I'd be very happy," how likely is he to retain his other gold medals?
"My focus is on trying to defend my titles," he says, "but then I have to be realistic and say the 400m and the 200m are the events I am better suited at."
Including heats, Pistorius could have to run seven races across eight days in his bid to win four gold medals in London.
Curbishley: "I think a lifetime best in the 200m is a realistic prospect. He will be pushed by Leeper and American Jim-Bob Bizzell but he is in form and in shape.
"In the 400m, Oscar is the overwhelming favourite but despite this, he still has to go through the rounds and the final and deliver.
"It has been a long season and he had a real emotional rollercoaster in running at the Olympics, so he will have to go and build himself up again and peak once again."