GP2 driver Felipe Nasr will make his Formula 3 comeback at this weekend's Euro Series finale at Hockenheim with Carlin.
The 20-year-old Brazilian, who won last year's British F3 crown with the team, was announced last week as part of Carlin's six-car line-up for the end-of-season Macau Grand Prix last week.
However, one of the rules of entry for Macau is that a driver must have competed in at least one F3 race during the same calendar year.
As a result, Nasr, who finished 10th with DAMS in GP2 this year, has signed up to partner Will Buller and Carlos Sainz Jr at the German circuit, which hosts the final round of both the Euro Series and the FIA Formula 3 Championship.
"It's been a busy year for me and at times it hasn't quite gone to plan, but the mileage and experience I've gained this year has been invaluable," Nasr said.
"I'm aiming to finish the season on a high before heading to Macau, which will be a fantastic experience.
This will be my first chance to drive the new F3 car, so it will be interesting to see how that compares to the car I won the championship in last season.
"The aim is just to get used to the power and characteristics of the F3 car again after a year of GP2 and help with set-up direction ahead of Macau. It will be really interesting to see how much of a difference there is between the new Dallara and last year's car."
Other one-off entries for Hockenheim include three Fortec cars for British F3 regulars Alex Lynn, Felix Serralles and Pipo Derani, and two new Volkswagen-engined Dallaras for Van Amersfoort Racing's Lucas Auer and Dennis van der Laar.
Prema Powerteam driver Daniel Juncadella currently leads both championships and is the favourite to claim both this weekend.
His team-mate Raffaele Marciello is his closest challenger in the FIA points while Mucke driver Pascal Wehrlein lies second in the Euro Series standings.