Formula 2 race winner Christopher Zanella will switch to Formula Renault 3.5 for this year, filling the second seat at ISR.
The Swiss driver, who has finished in the top three of F2 for the past two seasons, joins Sergey Sirotkin at the Czech team.
"This is a really great opportunity for me and I'm looking forward to starting the season," said Zanella.
"ISR has shown many times that it is an excellent place for a young driver to work and I intend to make the most of this opportunity."
Team boss Igor Salaquarda added: "I am very satisfied to welcome this driver who we believe is ready to race in a demanding category like Formula Renault 3.5.
"The kilometres of testing that we did together today [Tuesday] in Barcelona confirmed his ability to the team."
ISR fought for the FR3.5 title last year with Sam Bird, and it recently recalled the Mercedes Formula 1 test driver to help with its pre-season testing programme.
2013 Formula Renault 3.5 line-up so far: Tech 1 Racing Nigel Melker Mikhail Aleshin Arden Caterham Pietro Fantin Antonio Felix da Costa Fortec Motorsports Oliver Webb Stoffel Vandoorne ISR Sergey Sirotkin Christopher Zanella Lotus Marlon Stockinger Marco Sorensen Carlin Jazeman Jaafar Carlos Huertas Comtec Racing Daniil Move Lucas Foresti International Draco Racing Nico Muller Andre Negrao DAMS Kevin Magnussen Norman Nato P1 Motorsport Will Stevens Matias Laine Pons Racing Zoel Amberg Nikolay Martsenko AV Formula Arthur Pic Yann Cunha Zeta Corse TBA TBA