Wales great David Watkins -- the only man to captain the British Lions in both rugby union and rugby league -- has died aged 81, it was announced on Sunday.

An outstanding fly-half, Watkins was also a member of the Newport side when the Welsh club famously defeated the touring All Blacks 3-0 in 1963.

"We are extremely saddened to hear that David 'Dai' Watkins, one of the greatest players the club has ever produced, has passed away at the age of 81," said Newport in a statement posted on social media.

Newport's statement added: "We send our sincere condolences to his family, friends and everyone privileged to have known him."

Watkins won 21 Wales caps in rugby union from 1963-67, his Test career just overlapping with that of another brilliant Welsh fly-half in Barry John, who was in turn succeeded by Phil Bennett.

Watkins also captained the Lions' team in the third Test of their 1966 tour of New Zealand. But with rugby union then a strictly amateur game, Watkins joined English rugby league club Salford for £16,000 ($20,000) in 1967.

He won a further 16 league caps for Wales and six for Great Britain in the 13-a-side code before moving into coaching -- he was in charge of the Great Britain side that narrowly lost the 1977 World Cup final to Australia -- and administration in both sports.

England's governing Rugby Football League said Watkins would "be remembered as one of the best cross-code converts from Wales".

The ruling body added: "He became a key figure in a golden era for the Salford club, making more than 400 appearances for the Red Devils, and scoring almost 3,000 points as they were crowned champions twice in the space of three seasons in the mid-1970s."

Former Wales and Great Britain forward Jim Mills was among those to pay tribute to Watkins.

"Heartbreaking news the legendary David (Dai) Watkins has passed away, a wonderful player in both codes of rugby, the only man to captain the Lions in RU & RL," said Mills in a social media post.

"Dai was such a lovely man and will be greatly missed. He will never be forgotten. My deepest sympathy to his wife Jane & family."