Former Toyota and Sauber F1 driver Kobayashi is now part of Ferrari's GT driver stable in the World Endurance Championship.
He tried the Ferrari F10 in preparation for driving it at a promotional event in Moscow on July 21.
Kobayashi said driving an F1 Ferrari for the first time had been a very special experience.
Kobayashi's Ferrari F1 test in the AUTOSPORT news gallery
"The first feeling was one of great happiness," he said.
"I raced against this car and I knew how quick it was, so it was very important to get some experience of it.
"Last year's race in Brazil was the last time I drove a Formula 1 car and now I am racing in the WEC in a 458 GT and the impressions are completely different.
"But it wasn't hard to readapt, because in the past, I've driven all sorts of cars and I'm used to change.
"It will be very nice to drive an F1 car again at this event in Moscow and for me it will be a double debut: the first time at the wheel of a Ferrari F1 car in an event and my first visit to the city."
- Sports & Recreation