The Video Assistant Referee (VAR) system will be used in UEFA tournaments including the Champions League from next season, European football's governing body has confirmed.
VAR will also feature in the finals of Euro 2020 and at the 2019 UEFA Super Cup.
The Europa League will not use the technology until the group stage of the 2020-21 campaign and the 2021 round of Nations League finals, not those in 2019, will be the first to have VAR.
UEFA president Aleksander Ceferin said: "We are confident that introducing Video Assistant Referees in August 2019 will give us enough time to put in place a robust system and to train match officials to ensure an efficient and successful implementation of VAR in the UEFA Champions League, the world's flagship club competition.