Matt Ryan, pictured as John Constantine in "Constantine" Season 1, will reprise the role in "Arrow" Season 4. NBC

Fans have not seen the last of John Constantine! Many loyal viewers were disappointed when NBC announced it was canceling "Constantine" after just one season. "Arrow" star Stephen Amell was among the heartbroken fans, promising to guest star if the show returned via another distributor. While that does not look likely to happen, "Constantine" star Matt Ryan will appear on Amell's show, bringing the occult detective John Constantine to Starling City in "Arrow" Season 4.

According to the Hollywood Reporter, Ryan will appear in the season's fifth episode, aptly titled "Haunted," as his character helps Amell's Oliver Queen out with a spooky, supernatural problem in Starling.

"We are thrilled to have Matt Ryan reprise the role of John Constantine on an upcoming episode of 'Arrow.' Matt is an incredibly talented actor and his portrayal of this beloved character was always something we admired," said "Arrow" executive producer Marc Guggenheim in a statement. "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. It will be a well-deserved tip of the hat to all the 'Constantine' fans who were so incredibly supportive of that series."

Ryan teased his upcoming guest star appearance on Twitter Tuesday. The actor posted a video message to fans with the caption, "The Trench Coat is being dusted off."

"John is coming to Starling City," Ryan tells viewers. "I'll see you this fall."

As for Oliver Queen, the bow and arrow-wielding hero rode off into the sunset with Felicity (Emily Bett Rickards) in the Season 3 finale, but something has to bring him back home. "Arrow" can not go on without the Arrow, right? Apparently, some trouble with Thea (Willa Holland), who took over as leader of the League of Shadows at Season 3's end, could draw Queen back to Starling City. Plus, the show has reportedly cast actress Elysia Rotaru, who fans may remember from guest roles on “Supernatural” and the pilot of “iZombie,” in a recurring role as a new love interest for Oliver.

How will John Constantine factor in to all of the Starling City drama? Fans will have to wait to find out. "Arrow" Season 4 premieres Oct. 7.