This is being done to help UEFA and CONMEBOL build closer ties amid power struggles with FIFA over the future of soccer.
The move was often proposed in recent years by club coaches who felt an idea from the 1960s was no longer relevant.
Venues in St Petersburg, Munich and London have been selected by UEFA for the 2021, 2022 and 2023 Champions League finals.
Celtic will meet Slavia Prague if they reach the Champions League play-offs, Ajax perhaps have an easier draw, and Porto face a big test.