As filming on the last half of Season 4 of Supergirl continues, new recurring guest star Jon Cryer has teased his arrival on the DCTV series as Lex Luthor.In a post on his Twitter account, Cryer shared a behind-the-scenes photo of his monogrammed power ring bearing his initials and a gemstone. In the comic books, Luthor had worn a ring fitted with a piece of Kryptonite to keep Superman at bay though it is unclear if the gemstone in the ring is a radiated piece of Krypton given its clear color.RELATED: Supergirl Welcomes a New DC Villain to The CW in February

The Arrowverse incarnation of the character had been imprisoned by Superman for his crimes sometime before the events of the series with this season teasing that the character will reach out to his sister Lena from prison sometime in the second half of Season 4 to help with one of his plots.

The DCTV series received an early renewal from The CW for a fifth season to premiere sometime during the 2019-2020 regular television season so Season 4 may not be the last viewers see of Cryer's Luthor.

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Airing Sundays at 8 p.m. ET/PT on The CW, Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen and Chyler Leigh as Alex Danvers.