Christian Klien will compete in his first grand prix for four years this weekend in Singapore after coming to the aid of Hispania Racing.
Klien will replace Sakon Yamamoto, who earlier this season stepped in for Karun Chandhok, as the Japanese driver has been diagnosed with food poisoning.
Team principal Colin Kolles said: "It looks as if Sakon has food poisoning and he doesn't feel well.
"Because of this Christian will be driving the car today and for the rest of the Singapore Grand Prix.
"I hope Sakon gets well soon and is able to drive at his home grand prix in Japan (at Suzuka on October 8)."
Klien has at least driven for Hispania Racing in the first practice sessions for the Spanish and European Grands Prix this season given his role as test and reserve driver with the team.
However, the 27-year-old's last race was the Italian Grand Prix in 2006 when he was driving for Red Bull.
In the intervening years Klien has served as test driver with Honda and BMW Sauber, as well as competing in the Le Mans 24 Hours when he was third with Peugeot in 2008.