Although producer Guillermo del Toro declared just ahead of Comic-Con International that "a lot of the cast" of "Pacific Rim" will return for the Legendary Pictures sequel, Charlie Hunnam won't be among them.

"There was one incarnation of this sequel that involved me heavily, but I was unavailable," the actor told Yahoo! Movies while promoting "King Arthur: Legend of the Sword" at the convention. "They have a very definite schedule that they have to film. Because of the, you know, politics and business surrounding filmmaking, sometimes non-creative decisions will dictate how something unfolds, which seems bass-ackwards in the fact that we're making art. Or at least aspiring to make art.

"But, yeah, it unfortunately ended up being something we couldn't remedy, because by the time they got their schedule fully realized, then I wasn't available," he continued. "But I think they're on to something very exciting."

Directed by Steven S. DeKnight (“Spartacus,” “Daredevil”), the sequel to the 2013 sci-fi action epic is rumored to take place years after the original, when he enormous monster-fighting robots called Jaegers are commonplace. "Star Wars" actor John Boyega has been cast in a lead role that's reported to be the son of Idris Elba's Stacker Pentecost. "Suicide Squad's" Scott Eastwood is also said to star.

“Pacific Rim 2″ opens Feb. 23, 2018.