Wales coach Warren Gatland has agreed a deal to take charge of the British and Irish Lions on their tour of South Africa in 2021.
Although no contract has been signed, terms have been agreed by both parties for the New Zealander to lead the Lions for a third time.
Gatland has already overseen a winning tour of Australia in 2013 and a drawn series against the All Blacks four years later.
The Lions have yet to comment.
Gatland was also part of Sir Ian McGeechan's Lions coaching party in South Africa in 2009.
The New Zealander has said he will step down as Wales coach after the 2019 Rugby World Cup in Japan.
Wales won the Six Nations in March, extending their record-breaking run of winning matches to 14.
Since taking over with Wales in December 2007, Gatland has led his team to three Grand Slams and become the longest-serving coach in their history.
Gatland's start date with the Lions has yet to be confirmed, but given he will be a free agent after the World Cup, that is not considered to be a problem.
He was appointed less than a year before the Lions' 2017 tour of New Zealand, after the schedule had been decided. His early appointment this time will give him a chance to be involved in the advance detail and planning of the 2021 tour.
Furthermore, an announcement now will ensure Gatland can concentrate fully on preparing Wales' World Cup campaign, with the squad meeting for a preliminary training camp in the coming weeks.
Gatland's involvement with the Lions could increase the chances of him succeeding Eddie Jones as England boss. Jones is contracted until 2021, with the RFU expecting him to stay in the role after the World Cup.
However while Gatland has not ruled out a switch to Twickenham, formal talks have yet to take place, with the RFU currently undergoing major change at boardroom level.
BBC rugby union correspondent Chris Jones
Shortly after the tour of New Zealand, stung by criticism from the Kiwi media and Irish flanker Sean O'Brien, Gatland declared he was "done" with the Lions after a tour he "hated".
However, time has been a healer, with Lions officials desperate to lock Gatland down again after the success in Australia and the minor miracle he performed in his homeland four years later.
The timing works perfectly for Gatland, who can now concentrate fully on Wales' World Cup tilt, before becoming a free agent, which means he can start planning for South Africa early.
A third tour as head coach puts him in the exalted company of Lions legend Sir Ian McGeechan who led four tours.