Stephen Amell teased "Arrow" season 4 spoilers as he revealed that they are going to do something this time that has never been done before. Meanwhile, John Diggle will unveil a new costume based on the promotional photos.

During the Dragon Con 2015, Stephen Amell said, "The fundamental part of the season, that nobody is really going to understand until they see the premiere, is that we do something in the premiere that we've never done in the history of the show."

Stephen Amell further teased, "It does something for the remainder of the season that there's going to be a constant jeopardy in the show, even if times are good. It's a really interesting technique. I think it promotes a good story. I think it will pique people's interest."

Previous spoilers revealed that Constantine actor Matt Ryan would make an appearance in "Arrow" season 4.

"I've been filming scenes all week long with Matt Ryan," Stephen Amell said at the Wizard World Chicago last month. "He is such a treat. And a trip. He's always saying his lines -- and he's getting ready to go on Broadway right now with Kiera Knightley, so he's always saying those lines, too."

"I can't tell if he's having a conversation with me, or preparing. And sometimes I chime in, he'll be like 'I wasn't talking to you, mate.'"

Meanwhile, IGN published the promo pictures showing David Ramsey wearing John Diggle's new costume.

"The first shot showcases Diggle's new suit without the helmet or the jacket, which shows off a leather vest and a utility belt," it said. "The second shot (below), brings the helmet and jacket from the original revealed image back into play, and confirms that Diggle still prefers bullets over bows."

Watch out for more "Arrow" season 4 spoilers which will be published here when they come along.