Alexander Sims will stand in for Eric Lichtenstein in Carlin's GP3 squad for this weekend's round at Spa.
The 24-year-old, a factory McLaren driver in the Blancpain Endurance Series, has already competed in GP3 this year, finishing second at the Nurburgring for Status. He won with the squad during a full GP3 campaign in 2011. Carlin regulars Nick Yelloly and Luis Sa Silva will line up alongside Sims this weekend.
"It's been a bit of a last minute dash but of course I'm delighted to join the team for this weekend," Sims said. "I've never raced with Carlin before but I have a good relationship with Trevor and was delighted when I was offered the opportunity to race this weekend.
"The new GP3 car is fantastic and Spa is a great circuit, so I can't wait to get on track and hope I can deliver a strong result."
Team boss Trevor Carlin added: "We're very pleased to welcome super-sub Alexander to the team this weekend.
"It goes without saying that the team will work hard to help him familiarize himself with our car as quickly as possible. I know Nick is aiming for a top result this weekend which he is perfectly capable of and Luis should be aiming for his first points as well."