Nasr has been on the sidelines since losing his Sauber drive at the end of last season, and told Motorsport.com as recently as July he was actively working a return to F1.

However, the 25-year-old Brazilian conceded that a shortage of teams made a return to grand prix racing unlikely, resulting in him turning towards sportscar racing to further his career.

He will partner Eric Curran in Action Express's #31 Cadillac DPi-V.R next season, rekindling a partnership first formed when he made a one-off Daytona 24 Hours outing for the team in 2013.

Nasr replaces Penske-bound Dane Cameron in the #31 car, while former Audi factory driver Filipe Albuquerque steps in for Christian Fittipaldi as Joao Barbosa's full-season teammate in the sister #5 entry.

Fittipaldi will however remain on board for the four Tequila Patron North American Endurance Cup races, including the blue-riband Daytona, Sebring and Petit Le Mans events.

Toyota WEC regular Mike Conway will join Curran and Nasr for Daytona, Sebring and Petit Le Mans, reprising the third driver role he has performed for Action Express this season.

“As a team, the 2017 IMSA season has been a solid one, but we are all working hard to make 2018 an even better year,” said Action Express team manager Gary Nelson.

“We are happy to have Eric return in the Whelen Engineering [#31] Cadillac and to have Felipe come back to race with us for the full season.

"We have had the same driver line up for the Mustang Sampling [#5] Cadillac for the last two years, and that consistency will be an advantage.

"Christian, Filipe and Joao have all been racing with us but we are just changing the roles that each will have next year."