In just a matter of days, John Constantine (Matt Ryan) will be making his highly-anticipated appearance on Legends of Tomorrow. And it looks like he will bring something familiar with him on board the Waverider.

The Twitter account for Legends of Tomorrow's writers room recently shared a behind-the-scenes photo, captioned "Spotted on the Waverider." In the photo is a slip of paper bearing a phone number - the same one printed on Constantine's business cards.

Spotted on the Waverider... pic.twitter.com/YoRpYIMMNn — LoT Writers Room (@LoTWritersRoom) February 6, 2018

The phone number, 404-248-7182, has been a somewhat-consistent fixture of Constantine's live action appearances, beginning with his self-titled NBC television series. When the series first aired, the number was advertised as a working number, one that would play an Easter-egg-filled voicemail message recorded by Ryan when called. The number was reactivated (or, perhaps, never went away to begin with) when Constantine appeared on Arrow, leading to plenty of fans discovering the reference.

At this point, it's safe to assume that something similar will happen with next week's Legends episode, although it's hard to tell if the voicemail message will be the same. Arrowverse fans will just have to wait to find out.

The highly-anticipated episode of Legends will see John Constantine (Matt Ryan) joining forces with the team, enlisting their help in stopping some sort of supernatural threat. While it's hard to tell, judging by the photos, exactly what's going on, the end of Legends' midseason finale hints that it has something to do with the team's captain, Sara Lance/White Canary (Caity Lotz).

“I’ve gotten to work with Matt before on Arrow, although I think I was possessed pretty much the whole time,” Lotz said during a set visit last year. “He’s a fabulous actor; we had so much fun on set. I think Sara — he’s this really cocky guy who thinks he’s the s—t, and I think Sara kind of throws him for a loop because he thinks he’s so impressive, but then she…takes everybody down. I think they’re friends — they like each other.”

Legends of Tomorrow will return Monday, February 12th at 8/7c on The CW.