The 20-year-old will appear in a third Rahal Letterman Lanigan entry at the Indianapolis road course, having impressed team co-owner Bobby Rahal in a test at Barber Motorsports Park.
He becomes the second Danish driver to appear in the series this year, after ex-Formula 1 driver Kevin Magnussen made his debut in place of Felix Rosenqvist at Road America.
Lundgaard is able to compete this weekend as there is no clash with F2, where he currently sits 12th in the standings with ART Grand Prix during his sophomore season in the championship.
Fellow Alpine academy members Oscar Piastri and Guanyu Zhou currently head the F2 standings.
Speaking to select media including Autosport, Lundgaard said: “What I like about IndyCar itself is that it’s fairly similar to F2 but at the same time it’s a bit of mix of F2 and F1.
“It’s the big league but it’s the same cars. It’s a very competitive series, there is no power steering, the cars are physical to drive and it’s proper racing, where F1 I think we’ve seen over the past many years that it’s been mainly the same.
“I like the unpredictability. You’ve seen the race at Nashville with [Marcus] Ericsson going airborne at the beginning of the race and he ends up winning. Yes, you need some luck but it’s possible.
“I like the kind of racing that’s here. It’s different and you really have to fight for it and you push every lap, where in Europe it can potentially be a lot of tyre management and strategy that needs to work out. Here it’s more up to the driver to make a difference and everyone races hard.
“I don’t want to say too much before I’ve actually done a race so I have my own experience but it’s a very competitive series, there are a lot of cars too, and it’s exciting to watch, so I’m super excited to give it a try.”
However Lundgaard admitted that he has not given up hope of racing in F1. Alpine currently has Hungarian GP winner Esteban Ocon and Fernando Alonso under contract.
“At the moment, it’s still too early to decide – definitely before the race!” Lundgaard said of his future.
Marcus Ericsson, Chip Ganassi Racing Honda
Photo by: Chris Owens
“But I think having experience of the race and seeing how it panned out [will help].
“Obviously I have the F2 season we need to finish, and it’s about exploring options.
“I’m still with Alpine at the moment, but at the same time we need to figure out what to do. When it will be decided, I honestly can’t tell you because I don’t know.”
Rahal is expecting the Dane to show well this weekend, despite there being only one hour of practice time before qualifying, and is already trying to gauge his potential as the team’s third full-time entry next year.
“After Christian was introduced to us, we agreed to do that test and he did a very good job,” Rahal told Autosport.
“I think everyone on the team was quite impressed with him, in and out of the cockpit.”
But the 1986 Indy 500 winner admitted that any potential full-time driver would be required to run on both road courses and ovals, with the likes of ex-F1 driver Romain Grosjean and NASCAR legend Jimmie Johnson initially committing to the series on road course-only programmes.
“Any driver who races for us has to be ready to run the ovals as well as the road and street courses,” he added.
“I understand why some owners do that and split duties between two drivers in the one entry, but no, we have to have drivers who are strong in all types of races.”