The CW's Supergirl drops a major reference to WB's Smallville, hinting the shows may take place in the same universe. When the first season of Arrow debuted on The CW in 2012, many fans speculated whether it would hold up to Tom Welling's portrayal of Superman in Smallville, which had just completed a 10-season run in 2011. Of course, Arrow did find success as its own DC Comics television series, and even helped The CW launch an entire universe of shows, which now includes The Flash, Legends of Tomorrow, and Supergirl. While the majority of the Arrowverse takes place on Earth-1, Kara Danvers (Melissa Benoist) resides on Earth-38 - largely because the show started its run on CBS before moving to The CW for its second season.
Season 2 of Supergirl went a long way to developing Kara's world by officially introducing her superhero cousin Clark Kent aka Superman (Tyler Hoechlin) after only depicting the fellow Kryptonian in blurry or faraway shots in season 1. Superman has appeared in a handful of Supergirl episodes, but the show has made sure to keep its focus on its namesake. Still, we may have gotten some insight into Clark's life - and how it potentially ties into Smallville - in the latest episode of Supergirl, 'Midvale'.
Following the breakup of Alex Danvers (Chyler Leigh) and Maggie Sawyer (Floriana Lima) in the previous episode, Alex and Kara head to their childhood home in Midvale. However, much of the episode is a flashback to their time in high school as they try to the solve the murder of one of their classmates. When presented with a tech problem, Kara suggests they reach out to Clark's friend Chloe - presumably Chloe Sullivan - and Kara even mentions Chloe's Wall of Weird. Both of these are direct references to Smallville.
As fans will remember, Chloe was a character created for Smallville, not adapted from the comics - though she did go on to be introduced into the comics. Still, most know Chloe, played by Allison Mack, from Smallville. So, Kara's mention of her and her Wall of Weird could be the show's way of indicating the story of Smallville is a prequel to Supergirl - insofar as it's the origin story of Hoechlin's Superman and happened before Kara arrived on Earth. This would be an exciting revelation for fans of Smallville, especially those who have continued to keep up with DC Comics-based television by watching the Arrowverse shows.
Of course, there's one glaring error in the theory that Smallville and Supergirl are connected: Kara already exists in the world of Smallville, played by Laura Vandervoort. She debuted in the second episode of Smallville season 7, after Clark and Lois Lane (Erica Durance) stumble upon a spaceship. So, with Smallville featuring their own Supergirl, it's impossible for the show to take place in the same continuity as The CW's current superhero show.
Rather, it's much more likely that Supergirl and Smallville take place in separate universes, but The CW's show featuring the Girl of Steel simply wanted to include a fun reference to their TV predecessor. Undoubtedly, the new crop of DC Comics shows owe a debt to Smallville for paving the way for the current trend of small screen superheroes. Plus, considering the show has featured Vandervoort, 1984's Supergirl star Helen Slater, Lois & Clark: The New Adventures of Superman stars Dean Cain and Teri Hatcher, and more recently Smallville's Durance - not to mention Wonder Woman TV series star Lynda Carter - Supergirl has shown it's all about paying homage to the live-action superheroes that came before.