The FIA World Motor Sport Council has formally approved the contentious extra Pirelli 2020 Formula 1 tyre test, which will be run at Barcelona on October 7-8.
Mercedes, Ferrari and Red Bull have all offered to take part in the test, and in conjunction with the FIA Pirelli now must decide which teams will do it, as it had indicated that it might be possible for all three to run.
Pirelli had requested the extra test in order to prove its latest 2020 constructions on a high severity circuit, after it had completed its last planned running for next year's tyres with Mercedes at Paul Ricard earlier this month.
But as the testing schedule is part of the sporting regulations a change was required in order to allow the test to happen.
In theory at this stage - with the annual April 30 rules deadline having long passed - any such change would require the unanimous support of the teams.
Some were opposed on the basis that any team taking part would have an advantage by gaining extra knowledge of next year's tyres, despite it being a blind test with the results subsequently shared between all the squads.
But unusually on this occasion, the FIA accepted that a 70% positive vote would be sufficient, and after it achieved that the change was sent to the WMSC for approval.
Speaking before that approval was confirmed, Pirelli F1 boss Mario Isola made it clear that his company sees the extra running as essential.
"There was a request to run a test in Barcelona at the beginning of October to sign off the product for next year," he said.
"That means that we have now an indication of a certain specification of tyre that was going in the direction that was requested by the sport, when we started talking about a wider working range and a reduction of the overheating.
"When we started to develop the 2020 product we were basing our development on the old target letter.
"We were developing a new construction, a new profile, with different targets in mind, but not with a strong push to reduce the overheating again.
"When we started this the season the current product already reduced the overheating compared to last year, but then talking to the drivers they said we want another step in overheating reduction.
"Then there was all this discussion about the working window of the tyre. We had to modify out development programme to try to achieve these targets.
"At that point it was very, very late.
"If we want to do something more in the direction that I just mentioned we have to consider an additional test on a high severity circuit to sign off the product also on the hard and medium, the C1 and C2 compounds.
"Otherwise we miss this information, obviously. We run tests to confirm what we believe we are designing.
"We need track testing to confirm and validate the solutions that we have in mind.
"But it's not guaranteed - I cannot sign here that what we are going to test in Barcelona is what we expect. We run the test, we evaluate the result, and we will take a decision."
Pirelli had originally booked the Barcelona track on October 7-8 for 18-inch Formula 2 tyre testing.