Michael J. Fox and other celebs come to Philadelphia for Fan Expo

PHILADELPHIA (WPVI) -- This weekend the Pennsylvania Convention Center will be packed with pop culture mega-fans who are meeting their heroes in person.

Fan Expo is back with its biggest show yet, and this year's event features quite the celebrity lineup.

Stars of some of the most iconic films and series like "The Mandalorian," "Lord of the Rings" and "Harry Potter" are in Philadelphia right now.

There's also a very special reunion on tap: the cast of "Back to the Future."

"Michael J. Fox, Christopher Lloyd and Tom Wilson are going to be here," says Andrew Moyes, the vice president of Fan Expo.

"How electric to see them onstage together? Hayden Christensen is also going to be here this weekend. We're creating once-in-a-lifetime opportunities for them to come meet their heroes and also celebrate as a community."

Once known as "Wizard World," Fan Expo is expecting hundreds of thousands of people this weekend.

Fans of pop culture, sci-fi, horror, anime, and gaming can enjoy panels, workshops, shopping and more.

Artists from Marvel Comics were busy setting up their booths.

"We're here to see people and sell our work," says artist Jim Calafiore. "People come up and talk to us about the books. A lot of people bring books for us to sign, which is really cool."

You'll see famous film vehicles, like the DeLorean from "Back to the Future," and a Jeep from "Jurassic Park."

The "Ghostbusters" Proton Pack is also on display.

There are also meet-and-greets and workshops with famous voiceover artists like Jodi Benson, the voice of Ariel in the Disney animated classic, "The Little Mermaid."

Fan Expo runs through Sunday.