Nico Hulkenberg will make his first race appearance since he left the Renault Formula 1 team in the ADAC GT Masters series at the Nurburgring on 15-16 August.
The 2015 Le Mans 24 Hour winner will drive a Lamborghini Huracan GT3 Evo entered by championship newcomer mcchip-dkr.
He recently tested the car at the same venue, and is planning two more outings before the series' second round, which gets underway at the Lausitzring on 1-2 August.
Hulkenberg, who was dropped by Renault in favour of Esteban Ocon for 2020, stressed that his appearance doesn't mean that he is planning a bigger commitment to GT racing.
Germany's premier GT3 series features works supported teams and drivers from Audi, Porsche, Mercedes, Lamborghini and Bentley, with many squads also competing in the pro class of SRO's GT World Challenge Europe.
"The ADAC GT Masters is an exciting series with cool cars," he said.
"And after a break of almost eight months, I'm really keen to get behind the wheel again and feel the adrenalin flow.
"With Formula 1 at last having got underway, my fingers are twitching.
"To all rumour merchants out there, I'd like to make it quite clear that this guest start is to be interpreted as no more than a minor venture into GT sport.
"I'm really looking forward to the challenge, but I also know that we'll have to stretch ourselves quite a bit to be competitive."
Hulkenberg will share the car with mcchip-dkr managing director Danny Kubasik, who competes under the pseudonym 'Dieter Schmidtmann'.
"Because we are used to competing at a lower level of motorsport, the guest appearance in the ADAC GT Masters is a new chapter for us and a good opportunity to develop professionally as a team," said Kubasik.
"Entry in one of the world's most prestigious GT3 racing series makes us very proud."
Did you know?
Hulkenberg isn't the first ex-F1 driver to compete in ADAC GT Masters.
The likes of Heinz-Harald Frentzen, Karl Wendlinger, Jan Lammers and Mika Salo all contested events long after their F1 careers finished, while ex-Toro Rosso driver Jaime Alguersuari ended a three-year racing sabbatical to race a ROWE Racing Mercedes in 2014.
The Spaniard managed a best finish of seventh alongside GT regular Nico Bastian before going on to race for Virgin in the inaugural season of Formula E.