Williams won acclaim around the world for his fearless displays at fullback, and fractured his jaw and cheekbone in one tackle against Scotland and then also underwent knee surgery in 1974.

"I was very lucky during my career in not getting too many injuries. I hated not playing," said the 55-times capped Williams.

"I had to have the operation this week because I had been getting pain in my hip while I was in bed. It is what they call a 'Birmingham Hip' job, so I won't be laid up for too long.

"It does mean that I won't be able to be at the Millennium Stadium for Wales's last two games before the Rugby World Cup.

"I was really looking forwad to meeting up with some of the Argentinean management because it was on the trip to South America in 1968 that I first played for Wales at senior level.

"We played two uncapped internationals on that tour and we lost the first and drew the second. It was a fantastic trip for me to make as a teenager and it was a bit of an eye-opener.

"The Pumas were incredibly tough and committed then and they are the same now. It is going to be a very hard game for Wales on Saturday, but one that they can certainly win."

Williams will be throwing away his running shoes after the operation, but has been told he can carry on playing squash and cycling. His first task, though, is to be back in peak condition to follow Wales in the World Cup.

"I really want to be able to give my full support to Gareth Jenkins, Gareth Thomas and the rest of the Wales team," said Williams.

"I would have loved to have been given the chance to play in a World Cup. It must be the pinnacle of every player's career to play in a tournament like that.

"The current Welsh squad have got a great draw and I think they are going to be very, very competitive when the real action kicks-off."