Pal Varhaug, winner of the first GP3 Series race four years ago, will return to the category in 2014 with Jenzer, joining former Formula 2 star Matheo Tuscher.
Varhaug's victory in the inaugural GP3 round at Barcelona in 2010 was his only win of that year and he ultimately fell to 13th in the championship.
He subsequently moved up to GP2 as team-mate to future Formula 1 driver and 2011 champion Romain Grosjean at DAMS, but failed to score a point.
The Norwegian was then runner-up to Adrian Quaife-Hobbs in Auto GP in 2012, but only managed a handful of GP2 appearances with Hilmer last season.
Tuscher finished second in F2 in 2012, despite starting the season aged just 15 and with no top-level motorsport experience.
His Jenzer GP3 deal marks a return to regular competition after his 2013 season was limited to a Formula Renault 3.5 one-off for Zeta Corse.
Adderly Fong completes the Jenzer GP3 line-up, moving across from Status for a second year in the category.
2014 GP3 line-up so far: ART Grand Prix Alex Fontana/Dino Zamparelli/Marvin Kirchhofer Arden R Visoiu/P Niederhauser/J Mardenborough Koiranen GP Jimmy Eriksson/Carmen Jorda/Santiago Urrutia Carlin Alex Lynn/Emil Bernstorff/Luis Sa Silva Marussia Manor Racing Dean Stoneman/Ryan Cullen/Patrick Kujala Hilmer Motorsport Ivan Taranov/tba/tba Jenzer Motorsport Pal Varhaug/Matheo Tuscher/Adderly Fong Trident Victor Carbone/Roman de Beer/tba Status Grand Prix Nick Yelloly/Richie Stanaway/Alfonso Celis Jr