Carmen Jorda and Robert Cregan will compete for Ocean Racing Technology in the team's first season in GP3.
The Portuguese squad, which also races in GP2, announced on 7 March that it would take over from Tech 1 Racing for the 2012 season.
23-year-old Jorda competed in the Lamborghini Super Trofeo last year. She has previously raced in Indy Lights with Andersen Racing, in the LMP2 class of the 2009 Le Mans Series and has experience in both F3 Spain and the Euro F3 Open series. She is the second woman to sign for a GP3 team, following Vicky Piria's agreement with Trident Racing.
"I am delighted with this agreement, especially because Ocean is an experienced team in GP2," Jorda said. "I think we can develop and work well together. I'm sure they will help me to improve my performance. I am eager to test the car, that I am sure is very different from the Indy Light that was used to.
"I'll be a rookie in the championship but I'm sure I'll improve race by race. I must thank all those who helped me build this project"
Irish racer Robert Cregan meanwhile sat out both the 2009 and 2010 seasons before joining Matt Stone Racing for the junior 2011 Australian V8 Dunlop series.
Cregan, who tested for Tech 1 at the recent Estoril test, said: "I have already tested a GP3 car, but I also know that the first race will be hard and I have to learn a lot.
"The test next week will be very important. I trust in my ability to adapt to this new reality and hope to gradually improve. I think I will be able to run in the top five in the short term."