Fernando Alonso's decision to race for Toyota in the World Endurance Championship superseason alongside his Formula 1 commitments for McLaren means he now faces a gruelling 25-race schedule in 2018.
Alonso's deal to contest the 2018/19 superseason - which will include a first assault on the Le Mans 24 Hours later this year - was announced on Tuesday morning.
The Spaniard's season will start with the first four F1 grands prix in Australia, Bahrain, China and Baku, before he makes his WEC debut at Spa on May 5.
His most intense spell of the year will commence with the Canadian Grand Prix on June 10, which is the first of five consecutive race weekends the Spaniard will compete in that includes Le Mans on June 16/17.
F1's first triple-header of French, Austrian and British Grands Prix completes that run.
He will also face a mammoth three-weekend travel schedule at the end of the year that takes in the Brazilian Grand Prix, the Shanghai WEC event and then F1's season finale in Abu Dhabi.
Alonso's F1 McLaren programme will remain his priority this season, meaning he will skip the Fuji WEC round on the October 20-21 weekend to contest the United States Grand Prix.
Fernando Alonso's 2018 F1/WEC schedule
March 25 Australian Grand Prix
April 8 Bahrain Grand Prix
April 15 Chinese Grand Prix
April 29 Azerbaijan Grand Prix
May 5 WEC Spa
May 13 Spanish Grand Prix
May 27 Monaco Grand Prix
June 10 Canadian Grand Prix
June 16-17 Le Mans 24 Hours
June 24 French Grand Prix
July 1 Austrian Grand Prix
July 8 British Grand Prix
July 22 German Grand Prix
July 29 Hungarian Grand Prix
August 19 WEC Silverstone
August 26 Belgian Grand Prix
September 2 Italian Grand Prix
September 16 Singapore Grand Prix
September 30 Russian Grand Prix
October 7 Japanese Grand Prix
October 21 United States Grand Prix
October 28 Mexican Grand Prix
November 11 Brazilian Grand Prix
November 18 WEC Shanghai
November 25 Abu Dhabi Grand Prix