London - Warren Gatland was officially unveiled as the British and Irish Lions head coach for the 2021 tour to South Africa on Wednesday, revealing he had "unfinished business" against the Springboks.

Gatland will relinquish his role as Wales boss after the World Cup in Japan later this year and will start his official Lions duties in August 2020.

The 55-year-old will lead the Lions for the third consecutive tour, after winning the 2013 series in Australia and drawing with New Zealand in 2017. He was assistant to Ian McGeechan in South Africa in 2009.

"I'm hugely honoured and delighted to lead the Lions again," said Gatland. "It is exciting and a great challenge to coach the best players from the four Home Nations.

"The Lions rightly have a truly special place in the game and I jumped at the chance to be involved again when I was approached about the role. South Africa is a special place to play rugby."

He added: "Having toured there in 2009 I know the scale of the task ahead of us -- playing in South Africa presents a number of unique challenges such as playing at altitude, while the Boks will always be physical, aggressive and highly motivated.

"History tells you it's a tough place to tour but I am 100 percent confident that we can go there and win. I would not be here if I thought differently."

Gatland revealed he had "unfinished business" against South Africa, who won the 2009 series 2-1.

"Being a part of the Lions is an opportunity to go to South Africa and finish some unfinished business. We spoke about the potential and I couldn't turn my back on the challenge," he said.

The New Zealander admitted this would be his last tour as Lions head coach.

Gatland's long-term future remains unclear but he will first bid to leave Wales on a high at the World Cup.

The former Ireland boss was appointed as Wales head coach in 2007 and has guided the team to three Grand Slams.

Gatland now has the chance to become the first Lions boss to remain unbeaten on tours to Australia, New Zealand and South Africa.

"We're delighted to have got our man. Warren is a world-class coach, boasts a proven track record and knows the Lions better than anyone else currently coaching in world rugby, so naturally he was our first-choice candidate from the start of the process," said Lions managing director Ben Calveley.

"This was a unanimous decision from the Lions board and it was important that we moved swiftly and proactively to secure Warren's signature."