Van der Westhuizen sees a link
Joost van der Westhuizen believes it is possible there may have been a link between his rugby career and him being diagnosed with motor neurone disease (MND) in 2011.
Van der Westhuizen, part of the South Africa team that famously won the World Cup on home soil in 1995, picked up 89 caps for the Springboks and was his country's leading try scorer until Bryan Habana broke his record three years ago.
The 43-year-old is now in a wheelchair due to MND - a rare and debilitating condition which leaves the mind active as the body shuts down - and he spoke to BBC Radio Five Live with the help of his brother, Peter.
"It's not fair to say that rugby might be the cause. But there might be a link," he said.
When asked if he had suffered concussions during his career, he explained that he had broken his nose 16 times and "that should say enough".
Former London Irish full-back Jarrod Cunningham and ex-Western Province centre Tinus Linee died of the disease, but th ere have been no firm connections between high-collision contact sports such as rugby union and MND.
Van der Westhuizen revealed he has taken part in a study in the United States to investigate this further, adding: "I went to Boston to take part in research. We have to wait and see."
The former Bulls star now works to raise awareness of MND with his J9 Foundation and was recently seen taking part in the ice bucket social media phenomenon to draw attention to the disease.
On Saturday he will be a special guest at Twickenham when England take on the Springboks.
"Although my body is failing me my brain is 100 per cent. I am still alive and well," he added. "And I'm creating memories everywhere I go."
In the lead up to that clash, which sees both sides attempting to bounce back from respective defeats to New Zealand and Ireland last weekend, Van der Westhuizen paid a visit to England's training base at Pennyhill Park and made an impression on scrum-half Danny Care.
"He was one of my heroes growing up and it was brilliant this week to meet him, which was very inspiring and very humbling," Care said.
"He told me he was a fan of my game, which was unbelievable really. It took me back a bit to have one of my heroes say something like that about me."