British youngster Will Stevens has joined Alexander Rossi as an official reserve driver at Marussia.
Stevens, 23, currently races in the Formula Renault 3.5 championship and has previously conducted a couple of tests for rivals Caterham.
Stevens will take part in a number of free practice sessions across the remainder of the 2014 campaign.
"I’m really thrilled to be given this opportunity by the Marussia," he said.
"They are a great team, with enormous potential, and I’m so happy to be joining them at this exciting time in their development.
"Off the back of my F1 tests with Caterham, I can’t wait to get my first taste of the MR03. I’m looking forward to rewarding their faith in me and to making a positive contribution to our progress in the 2014 championship, and beyond."