Four-time F1 champion Alain Prost has compared Fernando Alonso's fascination for racing to that of seven-time title winner Michael Schumacher.
After a two-year sabbatical, Alonso earned the best result of his return with Alpine with sixth in Azerbaijan last time out after initially struggling to get to grips with the A521.
The Spaniard's comeback mirrors that of Schumacher, who retired at the end of the 2006 season before returning with Mercedes in 2010.
Speaking on the 'F1 Nation' podcast, Alpine special advisor Prost said of Alonso: "What impresses me the most, a little bit like Michael [Schumacher], that they are fascinated by racing and never stop.
"When Fernando is not on the track, he goes in the go-kart and obviously he has done many different things like endurance or Dakar or whatever.
"But he needs to drive. I never... I have done a few other things like Andros Trophy but that was completely different.
"Today, what surprises me also is Fernando is very professional and very honest with himself. He is very good for the team.
"You can always be a bit worried about what happened to Fernando in other teams but it is not the case today. He is very good so it is a big surprise but a good surprise. He is a very, very nice guy. Very nice."
Prost "not surprised" by Alonso needing time
Prost returned to F1 in 1993 after leaving the sport in the wake of being ousted by Ferrari at the end of 1991.
After his own experiences of returning, the Frenchman insisted Alonso's early-season difficulties were to be expected.
"I talked with Fernando last year before he started because I always remember when I came back, after only six months, I remember how difficult it is," added Prost.
"I was lucky that I could test the cars from September so I had... I don't know how many but I had a few testing sessions at the time and for him, it was only one day and a half in the car, except with the old car.
"So I am not surprised that he needs to have time. Not only knowing the car but the systems because it is more complex than what we had in the past, much more complex.
"The French Grand Prix is a different track, wider, a track he knows well, so we will see but I am not surprised it takes a little bit of time."