Renault Formula 1 junior Christian Lundgaard will replace Will Palmer at MP Motorsport for this weekend's GP3 round at Paul Ricard.
Lundgaard, who at 16 is more than a full year younger than every other driver on the GP3 grid, will make his series debut in what is described as a "one-off entry" for the second round of the 2018 season.
"It's a very big opportunity for me to be competing in the GP3 series," Lundgaard said.
"It'll be a whole new experience for me, especially driving a car with a lot more horsepower and downforce to what I'm used to.
"I'll be out there aiming to get the best results possible and trying to learn as much as I can in a short space of time."
Lundgaard was picked up by the Renault Sport Academy ahead of his full-time switch to car racing in 2017.
He embarked on a dual campaign with MP Motorsport in Spanish F4 and SMP F4 last year, winning both championships.
The Dane has remained with the Dutch outfit for his switch to Formula Renault this year, and currently sits second in the Eurocup standings.
"I know the circuit quite well from racing in the Formula Renault Eurocup this year, so I can take that as a small advantage," Lundgaard added. "A big thank you to everyone who has made this happen, I'll be giving it my best."
MP is making its GP3 debut this season, having taken over the entry that previously belonged to French outfit DAMS.
In replacing Palmer, who did not score points at the Barcelona GP3 season opener, Lundgaard will line up alongside Niko Kari and Dorian Boccolacci.