Another crossover can be expected in "Arrow," although it may be a stretch calling it so, considering that the series to cross with Oliver has already ended.

Matt Ryan, who plays supernatural con man John Constantine on NBC's "Constantine," is going to appear on "Arrow" as his demon-hunter character, reported USA Today. He will be appearing in the fifth episode of the season, aptly called "Haunted" when Stephen Amell's Oliver Queen finds himself struggling with paranormal problems.

Ryan himself confirmed the news on Twitter.

Marc Guggenheim, executive producer on "Arrow" said about Ryan, "Matt is an incredibly talented actor and his portrayal of this beloved character was always something we admired."

He also added, "The introduction of magic and mysticism on the show this season has provided a truly organic opportunity for us to bring John Constantine to Arrow and the CW's DC universe."

The news, according to The Hollywood Reporter, came after Amell offered to guest star on Ryan's series, should it see a second season -- which unfortunately didn't happen.

"Constantine," which also hailed from Warner Bros Entertainment, completed its first season last February and was officially canceled by NBC in May. Despite efforts, the series was not able to find another network, resulting to the cast and creators being released from their contracts.

"Constantine" fans better not get too excited, though. CW Mark Pedowitz said at the Television Critics Association Press Tour panel that "The series is no longer on the air and luckily, one of our parent companies Warner Bros. is the production company on 'Arrow' ... it's a great one-shot episode."

Details about Ryan's guest stint on CW's series are slim, and there isn't much that is known about the plot of that specific episode. However, as Cinema Blend noted, Constantine will be taking the trip to Starl City to hang out with Oliver.

While there is no news of Ryan appearing in other DC shows, his appearance on "Arrow" can open the possibility of Constantine being a recurring character in DC shows all across the board -- including "The Flash" and "Legends of Tomorrow."

Speaking of "The Flash," it was also revealed during the TCA that Teddy Sears will guest star as the old-school version of the speedster, Jay Garrick, courtesy of a comic book tribute to a 1961 story called "The Flash of Two Worlds."

"Arrow" will return for its fourth season on October 7th at The CW.