Former Red Bull Formula 1 test driver Brendon Hartley is to make his GP2 debut with Coloni at Monza this weekend and will stay on for Abu Dhabi season finale.
The New Zealander was dropped from Red Bull's young driver scheme earlier this year, losing his Formula Renault 3.5 drive with Tech 1 in the process.
But he will now return to single-seater racing to complete the GP2 season for Coloni, getting his first taste of the car in Friday practice in Italy.
"GP2 is F1's best feeder series so I'm really happy to debut in the championship, even though it will be a big challenge to do so at Monza," said Hartley.
"I'm very excited to be with Scuderia Coloni. They have been in the championship right from the start in 2005 and they have a great history and a lot of experience. So I'm confident that I can learn a lot and make the most of the little time I have.
"Obviously I have to keep in mind that I have never driven the car before and I'm competing against drivers that have contested the whole championship. Matching their performance won't be easy, I have managed to do a good job with the Coloni simulator and I'm confident that working with the team we will be able to improve steadily."
Team boss Paolo Coloni said the squad had plenty of faith in Hartley even though its expectations for Monza were limited given his inexperience with the car.
"We are very happy to have Brendon with us," said Coloni. "He is a highly esteemed and talented driver, who was selected by Red Bull Racing to be their test driver. This recognition is something very rewarding for the team.
"We face a really big task at Monza as Brendon has never driven a GP2 car, but he has great experience in high-powered cars and the team will support him in the best possible way. We are confident that working together we will be able to find the right pace in the little time available."
Hartley will replace Vladimir Arabadjiev alongside Alvaro Parente at Coloni.