Record Wales try-scorer Shane Williams told BBC Radio Wales: “It’s a surprise to me, especially with the way George is playing at the moment. It’s not as if he’s in bad form or carrying any injuries.
“I thought he had another couple of years left in those legs, at international level. It’s a real shame to see him go, he’s been fantastic since his debut through to now.
“When he made his debut in 2010, he scored two tries and his confidence went straight through the roof. He was a player of great ability; he trained well and was a real professional.
“That’s why he’s had this long career, he deserves everything he gets. George has decided to go out on his own terms, so good for him.
“It would be great to have him involved in the Welsh team for as long as possible, but only George knows how he feels.
“He’s been playing rugby a long time and it’s fair to say his body has taken a bit of a beating over the years.
“You know when it’s time to retire, your body tells you. You make a call; you look at your family and prioritise those guys.
“Only George can make that decision, he loves playing for Wales and if he thought for one second he could’ve got to the next World Cup, he would’ve done that.
“You’ve got to listen to your body and realise there’s more important things in life than rugby.”
Former Wales fly-half and captain Jonathan Davies said: “He’s been immense. We don’t breed many players of his pace and size in Wales, so when he came along he was like a breath of fresh air.
“He was the size of Jonah Lomu. Like Lomu he was a winger, but a Welsh winger.
“He did have huge impact and moments in games, whether it was for Wales or the Lions.
“It’s also the mark of the man how he’s come back from injuries.
“He’s had a few nasty bumps which could have dented or stopped his career and the way he’s responded has been great.
“To stay that long and be that physical player shows what a true professional he has been.”