FIFA has confirmed that video assistant referees will be used at the World Cup when the finals get underway in Russia in June.
The system allows referees decisions to be over-ruled when video replays show a clear and obvious error. The International Football Association Board had approved the move at a meeting earlier this month.
"VAR really helps referees," said FIFA President Gianni Infantino. "And it will help us have more transparent and fairer football, which is what we want."
Critics say that VAR interrupts the rhythm of matches.
FIFA also confirmed a fourth substitute will be allowed in matches that go to extra time.