It is the largest event of its kind in North Carolina and it's expected to bring in 50,000 people to the Raleigh Convention Center.
Organizers added a fourth day this year because of the demand last year -- this is third year this has been held in Raleigh.
"This is a great town," said Mike Broder, president of Galaxycon. "This building is great, the people in this city are great, the convention and visitors bureau have been phenomenal and they've been welcoming. Each year the show grows ridiculously. The enthusiasm in this town is unlike any we've been to."
The festival is more than a comic con, according to Galaxycon.
It's an "epicenter for superheroes, anime, fantasy, science fiction, video gaming, pop culture and more."
Fans will also get the chance to meet celebrities like Tim Curry from "The Rocky Horror Picture Show."
Visit Raleigh expects this to generate more than $5 million in direct visitor spending.
The convention starts Thursday. Saturday Full Day tickets are already sold out but there are still some Saturday After Dark (4 p.m. to 2 a.m.) tickets available.
Sunday tickets are still available.