When it was revealed at San Diego Comic-Con that the 100th episode of "Arrow" would take place during the annual crossover, many fans were worried. After all, 100 episodes is a momentous occasion and they were worried that celebration would take the backseat to fitting in "The Flash" and "Supergirl."

"When the news broke people were up and down my Twitter and Greg [Berlanti]’s Twitter ... and I think in this case in a very positive way," executive producer Marc Guggenheim says. "People didn’t want to feel like the crossover was hijacking what should be a really seminal episode."

Luckily, that won't be the case, as Guggenheim adds, "I think Greg came up with an idea that allows us to have our cake and eat it too."

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"It has some incredibly iconic moments. It is a love letter to the show," he continues. "It draws on all previous 99 episodes pretty much."

Luckily, it's going to include many familiar faces to the "Arrow"-verse. "Everyone who we could have in the episode from a scheduling point of view is in the episode," Guggenheim says.

Previously, it was revealed by star Stephen Amell that Deathstroke would return for the episode as one of the big surprises.

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What about the main cast though, beyond the notable guest stars? It seems they brought their very best work to the episode.

"There's one moment in it that I think is probably Stephen's finest performance to date. There's this one scene that really has two moments within the one scene that is just ... It will break your heart," Guggenheim says. "It will totally take your heart and pull it out and stomp it on the floor. It's very, very affecting. It's all on Stephen's back. It's incredible. Willa's amazing in the episode. Everyone obviously brought their A game to it. I'm really excited about it. It's the hundredth episode!"

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"Arrow" airs Wednesdays at 8 p.m. ET/PT on The CW.

Posted by:Chris E. Hayner

Chris E. Hayner is equal parts nerd, crazy person and coffee. He watches too much TV, knows more about pro wrestling than you do and remembers every single show from the TGIF lineup. You may have seen him as a pro-shark protester in "Sharknado 3." His eventual memoir will be called "You're Wrong, Here's Why..." TV words to live by: "I'm a firm believer that sometimes it's right to do the wrong thing."