(CNN) -- The life of rugby player Joost van der Westhuizen is the stuff films are made of -- literally.
The 43-year-old was part of the South Africa team which won rugby union's World Cup on home soil in 1995 and received the trophy from the late president Nelson Mandela as the post-apartheid era dawned.
The story of that victory was immortalized in acclaimed film "Invictus" and now, as he battles a life-threatening illness, Van der Westhuizen is drawing inspiration from that Latin word which means undefeated; unconquered.
Van der Westhuizen was diagnosed with motor neurone disease, also known as ALS, in 2011.
The man that famously muscled New Zealand rugby giant Jonah Lomu to the turf in the closely-fought 1995 World Cup final now uses a wheelchair to get around.
His body is too frail to walk because the debilitating disease effects all physical movement, including speech.
And the light and shade between his former glories and his present battle with illness is not unsurprisingly proving frustrating.
"It is," Van der Westhuizen told CNN's South Africa correspondent Robyn Curnow in a television interview where Van der Westhuizen's slurred speech has been subtitled. "But then again, that's how my life is."
The memories of his stellar career -- the Springbok jerseys and silverware -- line the walls of Van der Westhuizen's home in South Africa.
When he retired in 2003, he was the country's most capped player with a reputation as one of the most brilliant, and toughest, scrum halves in the history of the game.
Francois Pienaar, who captained South Africa to success in 1995, described Van der Westhuizen as "a phenomenal athlete."
"What Joost did on the rugby field was incredible," Pienaar told CNN. "He was probably the best number nine to play the game, and that's saying something."
Tough and tenacious on the rugby field, Van der Westhuizen is having to apply those skills in his fight to stay alive and help find a cure for motor neurone disease.
"I am," he assured CNN. "Without a doubt. I am a self-confessed bad loser and I want to beat this not just for myself but for everyone with ALS around the world."
Van der Westhuizen has started a foundation called J9 to raise money and awareness of motor neurone disease.
The foundation offers support and advice to patients and their families as they come to terms with a disease which has no clear cause.
A J9 legends team -- boasting over 500 international caps between them -- was cheered on by Van der Westhuizen in the veterans' tournament at November's Dubai round of the HSBC Sevens World Series.
He still travels around the world, often connecting with his old rugby rivals for fundraising events as well as making regular medical research trips to the United States.
It isn't just Van der Westhuizen's global mission which keeps him pressing on with his crusade.
"I am doing this to give my children a dad for longer," he says. "My daughter is eight, my son 10. They need a dad."
It is for this reason that Van der Westhuizen has revealed that he has decided to be artificially ventilated when his lungs are no longer able to function on their own.
It is a huge step for Van der Westhuizen given it's not common practice in his native South Africa.
"I am going to live as long as possible -- to help find a cure, to give my kids a dad," he said, confirming that he has made a decision about using an artificial ventilation machine, which will aid his breathing and help him stay alive
"There is nothing wrong with my brain or my heart. I am still alive."
Already a figure in one of South Africa's most historic sporting events, Van der Westhuizen is determined to defy the odds and help make history a second time.