Following the news that Supergirl season 4 will include classic DC villain Lex Luthor, fans are calling for Michael Rosenbaum to reprise the role he played for seven seasons on Smallville. We've already met a younger Lex on the show, in a season 2 flashback to his half-sister Lena Luthor's childhood. However, the Arrowverse's version of Lex has been soundly defeated by Superman and is currently locked up in prison, where he is theoretically supposed to stay for the rest of his life.
This season of Supergirl will actually return to the town of Smallville, the setting for the young-Superman show that ran for ten seasons on The WB and The CW, in the upcoming Elseworlds crossover. Casting for the role of Lex Luthor is set to begin soon, so you can probably expect to see him debut in the second half of season 4, in early 2019.
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Following the news of Lex's arrival in the Arrowverse, Smallville fans have been clamoring for Rosenbaum to return to The CW and play the bald-headed supervillain once again. Rosenbaum himself responded to one of these suggestions, and while he didn't indicate either way whether he would be interested in returning to the role, he did jokingly agree that his Lex Luthor was "underrated."
This wouldn't be the first time that an actor from a previous Superman show has joined the cast of Supergirl. Dean Cain and Teri Hatcher, the two leads of Lois and Clark: The New Adventures of Superman, played Kara's adoptive father Jeremiah Danvers and Mon-El's mother Rhea, respectively. Helen Slater, who played Supergirl in the 1984 movie, plays Kara's adoptive mother in the show, while Wonder Woman actress Lynda Carter plays the President of the United States. And while it might seem like a bit of a stretch to bring back Rosenbaum's Lex Luthor, despite Smallville not being officially part of the Arrowverse, it would definitely fit with Supergirl's love of fun and fan service.
The other question, of course, is whether or not Rosenbaum would be willing and able to join the show in a recurring role. This summer the actor started a podcast, Inside of You With Michael Rosenbaum, where a famous actor guests stars in each episode (the debut episode featured Smallville's Clark Kent, Tom Welling, and another episode featured Arrow actor Stephen Amell). However, he doesn't appear to have any major TV or movie commitments that would clash with Supergirl season 4. Could the fans actually make this happen?
More: Supergirl: 11 Big Questions After The Season 4 Premiere
Supergirl airs Sundays at 8/7c on The CW.