Harrison Ford is full of praise for his new costar, Michael J. Fox!

While attending the Shrinking FYC Event at Apple TV+ Emmy House, The Hollywood Athletic Club, in Los Angeles on Sunday, May 18, the actor, 82, spoke exclusively to PEOPLE about Fox, 63, joining the cast of Shrinking for season three. 

It marks the Back to the Future star’s return to on-camera acting following his 2020 retirement announcement amid his journey with Parkinson’s. The role of Fox’s character in Shrinking is yet to be shared publicly — but his casting reunites him with the series’ co-creator Bill Lawrence, whom he previously worked with on Spin City in 1996.

Ford tells PEOPLE he didn’t know Fox “very well” before he joined the Shrinking cast, but he has had the opportunity to meet him a few times throughout the years.

“His willingness to be part of our show is a great source of inspiration and gives us a real purpose,” Ford tells PEOPLE. “It's not just us coming together, two actors. There's a story to tell, and our commitment to the story is what joins us together. I appreciate his willingness to be a part of the show.”

In the series, Ford stars as Dr. Paul Rhodes, a therapist practicing mental health therapy while navigating his own Parkinson’s diagnosis. 

Parkinson’s is a “brain disorder that causes unintended or uncontrollable movements, such as shaking, stiffness, and difficulty with balance and coordination,” according to the National Institute of Aging. The disease worsens over time, with some people who have it experiencing “mental and behavioral changes, sleep problems, depression, memory difficulties, and fatigue.”

Ford said Fox is “pleased” the Apple TV+ series is “bringing Parkinson’s more into the light,” after dedicating his life to spreading awareness and raising money to fight the disease since publicly sharing his diagnosis in 1991 at the age of 29. 

He continued acting in Spin City from 1996 to 2001 despite his diagnosis and went on to star in The Good Wife before announcing his retirement. Fox launched the Michael J. Fox Foundation for Parkinson's Research in 2000.

Asked if working alongside Fox helped his portrayal of the disease, Ford tells PEOPLE, “I'm sure that there are subtle things that will show up later." 

“When we were together, it was an accomplishment of all of us trying to meet all the ambitions, both obvious and attendant, to the ideas we're trying to deal with,” he continues. “I've done what I could to acquaint myself with the aspects of the disease that I'm portraying, and I’m at a much different stage of the disease." 

“My character's in a much different stage of the disease than Michael's,” he adds. “But Michael, as Bill [Lawrence] points out, is totally there on the intellectual level. And emotionally, his humor and his courage are evident.”

Ford previously told PEOPLE he takes his role in the series “deadly f------ seriously.”

“There's no intention to make it into a joke, but there are people that absorb these kinds of experiences with grace and courage and a little bit of wisdom,” he said. “And that is not to say that some people do not.” 

“It's just to say that this is a person particularly equipped to communicate what it is that it's like, and that is something that I feel that is worth sharing with our audience,” Ford added.

Seasons 1 and 2 of Shrinking can be streamed on Apple TV+.