Rossi will be taking the seat of Marussia F1 driver Max Chilton, who has been subbed out "while contractual issues are resolved," according to the team's statement on Formula1.com.
"It goes without saying that I am thrilled to be given the opportunity to race in Formula 1 for the first time," Rossi said, according to F1.com. "I cannot thank the Marussia F1 Team enough for the faith they are demonstrating in me."
At this point, Rossi will fill in at this weekend's Belgian Grand Prix, at the legendary Spa-Francorchamps, only, with Marussia team principal John Booth saying the American's race debut wasn't originally in the cards.
"Naturally we hope to resume normal service with respect to our established race driver line-up as soon as possible, but for now we wish Alexander well for the weekend ahead and we look forward to seeing him in action," Booth said.