Jenson Button looks set to replace Fernando Alonso at the Monaco Grand Prix
McLaren's No 1 driver Fernando Alonso is contracted to race for the team until the end of 2017 but has been granted permission this week to miss the Monaco Grand Prix.
The Spaniard will instead travel to the US to race for Andretti Autosport in the Indy 500 where Alonso will drive a McLaren-branded, Honda-powered car.
F1 2017 Drivers' World Championship standings Sun, April 9, 2017
Express Sport runs through the current F1 Drivers' World Championship standings
Play slideshow GETTY 1 of 21
Who is top of the F1 Drivers' World Championship after Round 2?
And according to the BBC, F1 veteran Button will replace Alonso in a one-off appearance for McLaren after apparently retiring last year.
McLaren team boss Zak Brown said yesterday that a number of conversations had already been had about finding a replacement.
"Fernando's replacement driver is not in place," Brown said.
“Those conversations are ongoing.
“We have a few different options and we will state who that is when we know.”
Jenson Button sent a cryptic Tweet after Fernando Alonso announced his news
Get Quotes on Home Insurance
Button is understood to be the only viable option with the team not considering any of the drivers in the development programme ready to make the step up.
The Brit is officially McLaren's reserve driver but has been fulfilling an ambassadorial role for the team on what he terms his "sabbatical" year although he admitted at the end of the 2016 season that he had likely raced for the last time.
Jenson Button appeared to have raced for the last time in Abu Dhabi
But now it appears he will partner rookie Stoffel Vandoorne in Monte Carlo and will prove a valuable team-mate to the Belgian who will be taking on the legendary circuit for the very first time in an F1 car.
Button has won the Monaco Grand Prix before, driving to victory in 2009 on his way to F1 World Drivers' Championship glory with Brawn GP.