The 24-year-old Briton last competed in the series with Ocean in Malaysia last season.
He will drive the #23 car occupied by Pal Varhaug in the opening rounds.
Lancaster's most recent outings were in the winter MRF Challenge series in India.
His last full season in a major international series was in Formula Renault 3.5 in 2010.
He subsequently made occasional appearances in Auto GP and Formula 2 as well as GP2.
Lancaster will be the fourth driver to appear for Hilmer in its rookie GP2 season.
Varhaug contested the first two events, with GP3 racer Conor Daly his team-mate in Malaysia and FR3.5 champion and Sauber Formula 1 protege Robin Frijns taking the #22 car for Bahrain.