The fixture, the first-ever between the Lions and Japan, has been organised to help Gatland’s team prepare for the upcoming tour of South Africa which will culminate in a three-test series against World Cup champions, the Springboks.
Auckland-born Aki, who attended Manurewa High School, moved to Ireland in 2014 to play for Connacht, and made his debut for his adopted country in 2017 under New Zealand coach Joe Schmidt.
Aki will make his debut for the Lions against the Brave Blossoms, who are coached by Kiwis Jamie Joseph and Tony Brown, at Murrayfield.