The British & Irish Lions will host Japan at Murrayfield in Edinburgh before their tour to South Africa next year.
The Lions posted on their official website on Wednesday that the match is scheduled for Saturday, 26 June 2021.
It will be the first-ever clash between the Lions and the Brave Blossoms.
Lions head coach Warren Gatland believes the 2019 Rugby World Cup quarter-finalists will provide a stern test for his squad before they depart for South Africa.
"We saw Japan play some excellent rugby during the World Cup and they will come to Edinburgh fully-motivated to win," said Gatland.
"They are a talented side who play high-tempo rugby, so it'll be a good challenge for us ahead of the tour, and a chance for the match day squad to put their hands up for Test selection."
Lions managing director Ben Calveley added: "One of our objectives is to give Warren and the playing squad as much meaningful preparation as possible before departing on tour, so we are delighted to have agreed this fixture.
"A Lions Test is one of the most iconic events in world sport, but a huge number of fans from the home nations never get the chance to see one live. The Vodafone Lions 1888 Cup match will give even more supporters the opportunity to be part of the next chapter in Lions history.
"It will be an 'I was there' moment, against an entertaining and highly-respected opposition."
Japan head coach Jamie Joseph is also relishing the prospect of the fixture: "We are very much looking forward to playing a Test against the Lions next year.
"It is truly a once-in-a-lifetime opportunity for our players, and we can't wait for it to come."
The Lions tour for 2021 is set to take place over July and August with Tests at FNB Stadium (24 July), Cape Town Stadium (July 31) and Ellis Park (August 7).
Lions tour schedule in SA:
Saturday 3 July: British & Irish Lions v Stormers - Cape Town Stadium, Cape Town
Wednesday 7 July: British & Irish Lions v South Africa Invitational - Nelson Mandela Bay Stadium, Port Elizabeth
Saturday 10 July: British & Irish Lions v Sharks - Kings Park, Durban
Wednesday 14 July: British & Irish Lions v South Africa 'A' - Mbombela Stadium, Nelspruit
Saturday 17 July: British & Irish Lions v Bulls - Loftus Versfeld, Pretoria
Saturday 24 July (first Test): Springboks v British & Irish Lions - FNB Stadium, Johannesburg
Saturday 31 July (second Test): Springboks v British & Irish Lions - Cape Town Stadium, Cape Town
Saturday 7 August (third Test): Springboks vs British & Irish Lions - Ellis Park, Johannesburg