As part of the latest episode of his new YouTube series, Reunited Apart, Gad was joined by Christopher Lloyd, Michael J. Fox and Lea Thompson.
Seeing the reunion of Doc Brown, Marty McFly and his mom, Lorraine, was exciting for Gad, and will undoubtedly be a highlight for the film's legion of devotees. However, the host had more surprise guests in store.
Gad brought on the film's co-writer, Bob Gale, and director Robert Zemeckis, who helmed the movie and co-wrote the screenplay with Gale -- a screenplay that earned both men an Oscar nomination.
"This is heavy, seeing all of you on one screen right now," Gad said. "What is it like seeing this group back together again?"
"It feels like it was just yesterday," Zemeckis said with a smile.
"It's always great to see everybody, and this is new to see everybody like this," Gale added.
The group reminisced about the production and had fun recreating some iconic moments before a few more stars dropped by, including Mary Steenburgen, who played Doc Brown's romantic interest, Clara Clayton, in Back to the Future III, and Elisabeth Shue, who played Marty's girlfriend, Jennifer, in the Back to the Future II and III.
Gad even managed to pull in the film's composer, Alan Silvestri, and rock legend Huey Lewis -- who wrote and performed two of the most iconic songs from the film's soundtrack, "The Power of Love" and "Back in Time."
Toward the end of the chat, Gad asked the group if they had any ideas for what Doc and Marty could do or when/where they could travel if they ever decided to make a fourth film in the franchise, and Thompson had a very topical concept.
"I'd like them to go back to January  and they could warn us about coronavirus," she said with a laugh.
As for Gale, his idea was a lot more meta. "It would have to be that Doc and Marty find out that we're thinking about making another Back to the Future, and they come back to stop us from doing such a crazy thing."
This seemed to be a sentiment shared by Zemeckis, who basically shut the idea down.
"If I had an idea that I could have pitched to Bob with a straight face, we would have made it," Zemeckis explained.
With all the smiles and laughs from the cast, this virtual quarantine reunion will leave fans with a smile on their face.
"I've been doing a lot of revisiting of movies that were so important to me during my childhood. I've watched the pure joy on my children's faces as I've shown them those very movies that influenced my life," Gad said. "One night we were watching The Goonies, and it's always been a dream of mine to reunite that cast. I sort of just decided on a whim that I'm gonna do this, and I started reaching out individually, one by one."