When John Constantine arrives in the midseason premiere of DC's Legends of Tomorrow, he'll bring an Easter egg from his solo series along with him. The writers room behind the Arrowverse show revealed that the episode will feature a scrap of paper with the phone number from Constantine's business card.The phone number connects to a functioning line, which sends callers straight to John Constantine's voicemail. The voicemail message, as recorded by actor Matt Ryan, tells those who called in error to "sod off." However, if you're unlucky enough to be in need of his services, he instructs you to leave a number and lock your doors. The message concludes with a busy signal.RELATED: Legends of Tomorrow Summons Constantine in New Promo

The phone number debuted prior to the series premiere of NBC's Constantine in 2014. Originally, Ryan's Constantine told callers to "try the bloody swamp" if they were looking for Alec Holland, aka the Swamp Thing. The message switched to the one above after the series premiere. Constantine aired for one full season before it was cancelled, though the character subsequently made a cameo appearance on Arrow and will stick around for a two-episode arc on Legends of Tomorrow.

Returning Monday, February 12, at 8 p.m. ET/PT on The CW, DC’s Legends of Tomorrow stars Arthur Darvill as Rip Hunter, Dominic Purcell as Mick Rory/Heat Wave, Caity Lotz as Sara Lance/White Canary, Brandon Routh as Ray Palmer/Atom, Maisie Richardson-Sellers as Amaya Jiwe/Vixen, and Nick Zano as Nate Heywood/Steel.