Why was it introduced now?
UEFA decided to follow its introduction to this season's knockout season, after initially deciding to bring it back.
UEFA Chief Justice Officer Roberto Rossetti, who led the VAR project in the Champions League, confirmed the decision made following successful technology tests and training of judges in recent months.
"We are convinced that it will be beneficial to our competitions as it will provide valuable help to accommodate officials and will allow to reduce wrong decisions, Said the Italian, who took on the Euro 2008 final between Germany and Spain.
"We have held various courses in recent months with our Supreme Court justices and they welcome all the steps in order to ensure, in the end, the right decision is made.
"We've had good technology testing and trained the judges in the last few months and then we tested the VAR with selected adjustments and final preparations in all operational aspects, and now we are ready to implement VAR in the UEFA Champions League round of 16.