Fernando Alonso will take part in all rounds of the World Endurance Championship this year after a race was moved to accommodate him.
The two-time F1 world champion is dove-tailing his F1 commitments for McLaren with racing for Toyota in the WEC.
The Japanese race clashed with the US Grand Prix but in a sign of Alonso's pulling power it has been moved a week earlier than the F1 race in Texas.
The race at Fuji Speedway will now take place on 14 October.
The move was officially requested by Fuji but the track is owned by Toyota, so it effectively comes from Alonso's team.
It is believed to be the first time an FIA world championship event has been moved solely to ensure one driver can take part in it, and as such demonstrates the remarkable appeal Alonso has as one of the biggest stars in motorsport
From Alonso's point of view, it means the 36-year-old Spaniard can now target winning the WEC title as well as Le Mans, as he will be taking part in all races. He called it "awesome news" on Twitter.
Toyota said: "Fantastic for our Japanese fans that Alonso can also race in Fuji due to WEC date changes."
The move means Alonso will be competing in 21 grands prix and six WEC races in 2018.
He is also committed to doing the three WEC races in 2019 which also count to the new 'super-season' championship, a long as they do not clash with a grand prix if he is still racing in F1 next year.
McLaren executive director Zak Brown said he had no concerns about Alonso's workload.
"Fernando is very well prepared, knows what it takes to be successful and he wouldn't have taken on the additional commitment if he didn't think he could do both at the highest level," Brown said.
"It is no other agenda than he wants to race and he wants to win Le Mans.
"What would he be doing those weekends otherwise? He wouldn't be testing an F1 car or on the simulator.
"We have everything we need out of him on the F1 front so these are weekends he'd either be in a go-kart or golfing or whatever he wants to do. He'll just be in a WEC car. He wants to spend his spare time in race cars."
But Brown emphasised that F1 remains Alonso's main priority.
"While he is going to go there and try to win the championship, because that's what he does, when you think of Fernando you think of him as a McLaren Formula 1 driver first and foremost."
WEC boss Gerard Neveu said: "How could we have someone like Fernando Alonso in our paddock, racing for Toyota, and say we are going to Japan without him in their car?
"Alonso is racing for a World Championship and to win that he can't miss a race."
The date change means the Fuji race now clashes with a sports car race in the IMSA series in the USA, in which some of the drivers in the WEC are racing.
Neveu said IMSA "fully understood" the situation and Alonso hoped it would be able to move the date of that race.