Michael J. Fox and Christopher Lloyd Reunite at Comic-Con, 37 Years After Back to the Future

Michael J. Fox and Christopher Lloyd enjoyed another epic trip to the past this weekend.

The Back to the Future actors reunited on stage Sunday at New York Comic-Con, 37 years after the classic Robert Zemeckis film first hit theaters. It marked their first reunion since they joined forces with other cast members on Josh Gad's pandemic YouTube series, Reunited Apart, back in 2020.

Fox, 61, and Lloyd, 83, used the event to think back to their first encounter with each other, which came after Fox replaced Eric Stoltz in the lead role of Marty McFly, weeks after filming had begun.

RELATED: Michael J. Fox Remembers His Mom 2 Weeks After Her Death at Back to the Future Comic-Con Panel

"The announcement at one o'clock in the morning after we were shooting for six weeks, was that the actor playing Marty would no longer be playing Marty and that tomorrow, we would start shooting with Michael," Lloyd said. "I felt that I barely made it through the [first] six weeks and now I was gonna have to do it again... There was immediate chemistry, as they say."

Mike Coppola/Getty for ReedPop

Fox — who at one point said he'd have to "watch my a--" because of how talented his costar was — gushed about working with his longtime friend on the three-film series, and said that when it came to acting alongside Lloyd, "all I had to do was react."

For more on Michael J. Fox and Christopher Lloyd's reunion, listen below to our daily podcast PEOPLE Every Day.

"Just take it in and let it wash over me. I thought he was brilliant," Fox said. "That was the whole thing: be with Chris and let it be Chris, and enjoy it... It was a thrill. Anytime I got to work with him, I knew it was gonna be a good day."

RELATED: Back to the Future: The Musical Coming to Broadway in 2023 — Watch the First Teaser

Mike Coppola/Getty for ReedPop

The film, which was put together on a $19 million budget, ended up earning $388.8 million at the box office. Back to the Future II, released four years later in 1989, cost double the original film's budget and had a box office turnout of $332.9 million.

RELATED: Rachael Leigh Cook, Christopher Lloyd Starring in Movie About a Haunted Spirit Halloween Store

While the pair certainly shared some gems from making the movies and their thoughts on Back to the Future: The Musical, they also touched on their relationship off-screen — most notably, Lloyd's role in Fox's life since he revealed his diagnosis with Parkinson's in 1991.

"Parkinson's is the gift that keeps on taking. But it's a gift, and I wouldn't change it for anything," Fox said. "People like Chris have been there a lot for me, and so many of you have. It's not about what I have, it's about what I've been given, the voice to get this done, and help people out."

Also at the Comic-Con panel, Fox opened up about finding "something to be grateful for" despite sustaining some injuries this year and paid tribute to his late mother Phyllis, who he shared died on Sept. 24 at age 92, just two weeks before the event took place.

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

"To this day — well, till two weeks ago — my mother thought it was a really bad idea for me to do Back to the Future," Fox joked about his mother, who told him that making the Steven Spielberg-produced movie alongside his TV work on Family Ties, would make him "too tired."

"She loved the movie, [but she was right]," joked Fox. "I got tired!"