From John Travolta to Zachary Levi, here are all the celebrities in Boston this weekend for Fan Expo

Celebrities are descending in droves this weekend for Fan Expo Boston, an annual pop-culture convention spanning Friday, Saturday and Sunday at the Boston Convention & Exhibition Center.

John Travolta, of “Grease” and “Pulp Fiction” fame, will appear Sunday afternoon for a panel on the show floor’s main stage (around 2 p.m.), also participating in paid photo opps with fans throughout the day.

His is an especially noteworthy appointment, given that the actor has never appeared at a convention before. Travolta’s supporting new film “The Fanatic” which has an exclusive sneak preview Saturday two weeks ahead of its Aug. 30 release.

In a rare convention appearance, reclusive “Spawn” creator Todd McFarlane is set to speak during a fan Q&A on Sunday (at 2:30 p.m.); it’ll be the artist-scribe’s first Boston-con gig in over two decades.

Zachary Levi, who starred in Warner Bros/DC superhero blockbuster “Shazam!” earlier this year, is in town all weekend, with photo opps across all three days and a Q&A discussion set for 11 a.m. for Saturday.

Some others making a three-day con-mittment include “iZombie” actress Rose McIver, “Goonies” actor Ke Huy Quan, “Power Rangers” alum Jason David Frank, comic-book creators Marc Silvestri (“Uncanny X-Men”) and Mike Mignola (“Hellboy”), “Saturday Night Live” vet Rob Schneider, and the “Boy Meets World” team of Will Friedle, Ben Savage, William Daniels, and Rider Strong (their co-star Danielle Fishel joins on the latter two dates).

Saturday and Sunday are set to be busier than Friday, with two-day stints by Peter Capaldi (“Doctor Who”), Sean Young (“Blade Runner”), “Goonies” actors Corey Feldman and Sean Astin, “Teen Wolf” actor Tyler Hoechlin, “Once Upon a Time” star Jennifer Morrison, “Luke Cage” protagonist Mike Colter, and “The Walking Dead” fan favorite Laurie Holden.

Stephen Amell, of “Arrow,” is stopping in Saturday.

Voice actors scheduled to be in attendance include Jodi Benson (“The Little Mermaid”), Rodger Bumpass (“SpongeBob SquarePants”), Peter Cullen and Frank Welker (“Transformers”), Grey DeLisle (“Fairly OddParents”), John DiMaggio (“Futurama”), Vanessa Marshall (“Star Wars: Rebels”), and Patricia Summersett (“The Legend of Zelda: Breath of the Wild”).

In addition to all the celebrity appearances, most of which are accompanied by panels, over 500 retailers are setting up shop at Fan Expo to peddle their geeky wares, including everything from T-shirts and toys to vintage comic-books and collector’s items. A walk-on costume contest, tattoo booths, workshops, seminars, celebrity photo and autograph sessions and more await attendees.