GALLERY: Joost van der Westhuizen through the years
Health24: What is motor neuron disease?
News that former Springboks captain Joost van der Westhuizen has a serious motor-neuron muscle disease was "distressing in the extreme," South African Rugby Union President Oregan Hoskins said.
In a statement, Hoskins offered rugby's "support and prayers" to Van der Westhuizen, a day after the 1995 World Cup winner's publicist said he was being treated for the disease.
Reports on Friday said Van der Westhuizen was in a hospital in Johannesburg.
There was widespread media coverage of Van der Westhuizen's illness in South Africa on Friday, with the 40-year-old former scrumhalf still considered one of the country's greatest ever players despite a string of personal scandals that led to the much-publicized disintegration of his marriage.
"The thoughts and prayers of SARU, the Springboks and the South African rugby community are with Joost and those nearest and dearest to him at this challenging time," Hoskins said. "He was an outstanding Springbok and is a legend of our game - he will always have a place of honor in the history of Springbok rugby.
"He gave his all on the field for the teams he represented and - at his prime - was the best scrumhalf in world rugby. His current health problems are the cruelest twist of fate for one who was so athletic in his prime."
Van der Westhuizen played 89 tests for South Africa from 1993-03 and still shares the Springboks' try-scoring record in tests (38) with current wing Bryan Habana. He is the fourth most capped player ever for South Africa.
On Thursday, publicist Bridget van Oerle said Van der Westhuizen had been diagnosed with a "serious muscle-related neural disease" by his doctor after having trouble with his right arm. No exact name or details of the condition were given.
"Van der Westhuizen also consulted two neurologists," Van Oerle said, "and has began immediate treatment. The symptoms are serious and vary from person to person."
Van Oerle's statement also requested privacy for Van der Westhuizen and his family after his personal life was subjected to intimate scrutiny in recent years.
In 2009, he was taken to hospital with what was announced as a suspected heart attack - that proved later to be incorrect. He divorced from his wife, a local singer and actress, in 2010 after allegations of drug-taking and infidelity which were splashed across South Africa's showbiz media.
His feats on the pitch are still respected by many rugby fans, however.
Van der Westhuizen emerged as one of the world's best scrumhalves when South Africa famously won the World Cup on home soil in 1995 - the story that inspired Clint Eastwood's Hollywood film "Invictus."
During his 10-year career, in which he appeared at three World Cups, he gained fame for his sniping runs and tryscoring abilities.
But, much taller than an average scrumhalf, he also earned a reputation as a ferocious defender and - above everything - a player with an unflinching will to win.
"I just hated losing," Van der Westhuizen said on South African television this month in a program recalling the Springboks' 1999 World Cup campaign - where he captained the team to the semifinals.
His last game for his country was a loss to fierce rival New Zealand in the quarterfinals of the 2003 tournament, after which he retired as South Africa's most capped player ever.
His 89 tests have since been overtaken by Percy Montgomery and current Boks pair John Smit and Victor Matfield.
After retiring, Van der Westhuizen spent five years as atelevision pundit and released an autobiography in 2009 entitled 'Spieelbeeld' - or 'Man In The Mirror' in his first language, Afrikaans.