"Arrow" season 4 episode 5, titled "Haunted," was uploaded to Torrent sites on Nov. 1, Sunday. The well-anticipated episode of the CW series features the crossover of two DC characters, Green Arrow and Constantine.

This week's episode of Arrow season 4 has been pirated three days before its intended release date on The CW Network.

Matt Ryan, the actor who portrays John Constantine, is set to reprise his role on "Arrow."  John Constantine was the central character in his own show on NBC during the 2014-2015 season. NBC eventually cancelled the series after 13 episodes, due to low ratings in its time slot.

Although the ratings did not reach its standards, the series gained a cult following and a huge fanbase. One of the known members of the fanbase is Stephen Amell, the protagonist in "Arrow."

The show's cancellation compelled fans to file a petition in order to bring the series back. Amell even announced on his Twitter account that he would make a guest appearance if "Constantine" would be picked up by another network.

When the petition failed, Amell figured out a way to bring the character to his own show.

The leaked "Arrow" episode has been downloaded more than 11,000 times through Torrent, according to Deadline. The source of the leak is still not known.

Magic and mystic has been the main theme of "Arrow" season 4, which gave a hint that John Constantine may be in it. Since Sara Lance's resurrection from the Lazarus Pit, Laurel (Katie Cassidy) and Detective Quentin Lance (Paul Blackthorne) have been struggling in terms of how they will deal with a newly revived Sara.

"Haunted" will depict Arrow asking help from John Constantine on how to deal with Sara Lance. According to speculations, this may serve as an advance set up before the release of CW's "Legends of Tomorrow" that also features Sara Lance as the White Canary.

How the leaked episode will affect TV ratings is yet to be seen, even with the early positive reviews.

Fans can catch Constantine on "Arrow" on Nov. 4 at 8 p.m. on The CW.