In a shock announcement, McLaren's Fernando Alonso will contest this year's Indy 500, and will therefore miss the Monaco Grand Prix.
Alonso will race a McLaren entry run by Honda-powered Andretti Autosport, the Indycar outfit owned by Michael Andretti.
"I'm immensely excited that I'll be racing in this year's Indy 500, with McLaren, Honda and Andretti Autosport," said Alonso.
"The Indy 500 is one of the most famous races on the global motorsport calendar, rivaled only by the Le Mans 24 Hours and the Monaco Grand Prix, and it's of course a regret of mine that I won't be able to race at Monaco this year.
"But Monaco will be the only 2017 Grand Prix I'll be missing, and I'll be back in the cockpit of the McLaren-Honda MCL32 for the Canadian Grand Prix in Montreal in early June."
The announcement is a major marketing coup for Indycar and the Indianapolis 500, although a major surprise given Formula 1 teams' completel reluctance to allow a driver to race in a different category, let alone in a form of specific racing as the Indy 500.
But the endeavour also serves as a reminder of McLaren's heritage at Indy, with the team having won the prestigious event twice, in 1974 and '76 with Johnny Rutherford, while Roger Penske's private McLaren entry won with Mark Donohue in 1972.