McLaren's Fernando Alonso will drive a Toyota LMP1 car during Sunday's World Endurance Championship open test in Bahrain.
The two-time Formula 1 world champion attended a seat fitting at the Japanese manufacturer's racing headquarters in Cologne two weeks ago, in anticipation of a potential race programme in 2018.
Alonso has been heavily linked with a drive at next year's 24 Hours of Le Mans, which Toyota is set to participate in as the only LMP1 hybrid entrant.
The Spaniard attended Saturday's WEC 6 Hours of Bahrain (above) as a guest of the Bahraini royal family, and saw Toyota claim victory in the final race of the 2017 campaign.
"We are very excited that Fernando will test our car," said Toyota Gazoo Racing president Histake Murata.
"We very much respect his interest in different forms of motorsport and it is a pleasure to offer him this chance to drive a hybrid LMP1 car. It will be interesting to hear his feedback on the TS050 Hybrid."
"When he visited us in Cologne everyone who met him could sense his enthusiasm and passion for our sport; he is a true racer."
Joining Alonso behind the wheel of the Toyota TS050 will be rising LMP2 star Thomas Laurent, who finished second overall at Le Mans this year with the Jackie Chan DC Racing outfit.
The pair will be joined by several other teams on-track during the five hour test, which will also see an LMP1 debut for recently crowned Formula V8 3.5 champion Pietro Fittipaldi.
The grandson of two-time F1 world champion Emerson Fittipaldi will sample a Porsche 919 Hybrid as a reward for clinching the series title on Saturday.
