The 21-year-old Frenchman, who impressed with sister team Racing Bulls last season, said the reality had still not fully sunk in as he teams up with his idol who he watched win four championships with Red Bull.
"It's a bit unreal for me. I've always dreamed of driving for this team as a kid watching TV. I saw (Sebastian) Vettel winning all those titles and now I'm finally in the big team," Hadjar said as Red Bull revealed their 2026 car livery in Detroit.
A string of hopefuls have failed to match Verstappen's relentless pace in Formula 1, with the Dutch driver set to start the 2026 season with his fourth different teammate since the last race of 2024.
Sergio Perez, Alex Albon, Pierre Gasly and Tsunoda have all fallen by the wayside but the transition for Hadjar should prove smoother than most having spent years climbing through Red Bull's development ranks.
"The Red Bull family have been in it for a couple of years now since I signed up in the program as a kid. So it's not fully new to me," Hadjar said.
"I'm lucky enough not to have to meet everyone the first time, there are familiar faces, also a couple of mechanics. I started to work quite early in the season to make sure I'm fully adapted and fully in the rhythm."
As for his 2026 goals having secured a podium with third place in the Dutch Grand Prix in his rookie season, Hadjar said: "A race win would be good, at least."
The 2026 season marks the start of a new engine era with an overhaul of the technical regulations and Verstappen, who lost the 2025 title to McLaren's Lando Norris by two points, said drivers would need time to get used to them.
"It's all still a bit unknown," he added. "It's a very big, big change with the engine, the car. You can see also the dimension of the car has changed a bit.
"So for us drivers, initially we'll take a bit of time to adjust. That's why it's very important during the test days that we are getting our laps in and we can optimise everything as well as possible."