The 21-year-old will take to the wheel of the MR02 car at the Kemble airfield tomorrow to conduct a scheduled straightline aerodynamic evaluation.
Ellinas, currently in his second GP3 season, had already secured the chance to drive a Formula 1 car when he was confirmed for this year's young driver test at Silverstone next month.
"It goes without saying that I am thrilled to get this additional opportunity to drive the MR02 race car," said Ellinas.
"I have been looking forward to the young driver test since last Autumn and the weeks can't pass quickly enough.
"Being able to conduct the straight line test this week will help to bridge the gap until Silverstone and will also mean I can hit the ground running there as I will already be familiar with the car systems and the team's procedures."
Team boss John Booth added: "Tio has done a very impressive job for our GP3 team over one and a half seasons now.
"We were very pleased to welcome him back for a second term and even more delighted when he brought us our first victory of the season in the opening round in Spain.
"He is definitely a star of the future and deserves both of the opportunities that we are putting his way, starting with this week's aero test at Kemble."