Ottawa Comiccon's celebrity guest list features stars from The Princess Bride and the man behind the iconic Batman voice in the animated series.

The annual event, which attracts more than 40,000 people to celebrate comics and multi-genre entertainment, will take place at the EY Centre May 10 to 12.

The conference's spokesperson said others will be added to the growing list.

"[We announced] some heavy hitters today just to get people excited," Jason Rockman told CBC Radio's All In A Day Friday.

The guest list so far includes Pom Klementieff from Guardians of the Galaxy Vol. 2, Mark Sheppard from Supernatural and Cary Elwes from The Princess Bride.

Actor Cary Elwes, known for his role as Westley in The Princess Bride, will make an appearance at Ottawa Comiccon this year. (Getty Images)

"Elwes is wonderful and so many people are excited," Rockman said. "He's a fan favourite."

Comiccon also announced Friday that The Princess Bride's Wallace Shawn, the voice behind Rex from the Toy Story franchise is part of the lineup, as well as Mike Colter from Luke Cage, John Barrowman from Arrow and Kevin Conroy, the voice of the Batman animated series.

Wallace Shawn is best known for his roles in The Princess Bride, My Dinner with Andre and in the Toy Story franchise, where he voiced Rex the dinosaur. (Chris Pizzello/Associated Press)

"When you get the voice actors they're awesome because they have so many stories," Rockman said.

"They've got to approach acting from a completely different place. It has nothing to [do with] their looks, it's all about the voice."