Stephen Amell and Grant Gustin Tease 'The Flash' and 'Arrow' Crossover Episodes

The much-anticipated crossover episodes of "The Flash" and "Arrow" are right around the corner, and we've got the scoop on what's in store for Barry Allen, Oliver Queen and the gang.

ExtraTV.com caught up with Stephen Amell, Grant Gustin and friends on set in Vancouver to find out more, but first, here is a little background on the two episodes.

In the Dec. 2 episode of “The Flash,” called “Flash vs. Arrow,” Oliver, Felicity and Diggle travel to Central City to investigate a case involving a deadly boomerang. During the visit, Barry asks Oliver to help him stop a bank robber and meta-human named Ray Bivolo, who can cause people to lose control of their emotions.

When Bivolo uses his powers on Barry, the Flash goes into a rage and the only one who can stop him is the Arrow.

In the Dec. 3 episode of “Arrow,” called “The Brave and the Bold,” Oliver, Arsenal and Diggle are still searching for the boomerang killer, Digger Harkness. When he targets Lyla, Oliver recruits Barry to help.

Stephen told reporters, “Starling City and Central City are very different places. So when I go to Central City, it's very much, 'Alright, I'll tag along. We'll do things your way.' And then the very next night, in our episode, it's 'I'm sorry, we're not in Central City anymore. We're doing things my way. Things are different here.'”

He continued, “So it's a really interesting checkpoint for both shows because we're able to teach these big lessons to the characters. So hopefully Oliver comes out of his trip to Central City having learned something and Grant comes out of his trip to Starling City having learned something as well.”

Amell added that you can bet based on the “Flash vs. Arrow” title that “we are going to fight.” “[It] was a very new and different experience for me just from a technical standpoint because 'The Flash' has so many effects… I actually had to do a move where I'm going to punch and I had to punch in slow motion and literally do slow motion faces and all that stuff.”

What did he like best about the episodes? “The unequivocal highlight of the entire crossover for me is David Ramsey (Diggle). I could not keep a straight face during any of David Ramsey's lines during the crossover to 'The Flash.' It destroyed me.”

As far as interacting with “The Flash” personalities himself, he said, “I personally really enjoyed working with Carlos. He's just a very, very fun character.”

He also teased, “I think that one of the most interesting parts about the whole episode is an observation that Oliver makes about Harrison Wells.”

Meanwhile, Gustin noted that the episodes highlight Barry and Oliver's differences. “Barry and Oliver are kind of butting heads but we're seeing them learn how to work together. It's really funny because they're so different so the conversations they have are hilarious."

He agreed with Stephen that Diggle's lines are some of the best in the crossover. “David Ramsey is, like, the funniest person in the world… Diggle seeing the Flash, and who Diggle is, and having to accept that this is reality. And he just plays that so well and so funny. It's great.”

Danielle Panabaker also teased what's in store for her character Caitlin and buddy Cisco, explaining, “There's this sort of element of fun and fantasy that they have and they're just sort of on the phone with the Flash, helping him do incredible things like save kids from burning buildings, but when they're on the 'Arrow,' really terrible things happen and they're forced to deal with the reality of death and consequences… in a very immediate way that they don't generally get when we're in Central City.”

As far as Iris (Candice Patton) is concerned, it's all about the eye candy. Patton revealed Iris isn't involved in any major action, but she does have a run in with Oliver at Jitters. “Iris makes very well of Stephen. Iris likes Oliver. It is just fun, but I don't want to give it away because it is so fun.”