Marc Guggenheim is developing a new, secret project for DC.The Arrow and Legends of Tomorrow co-creator announced the project on Twitter, though he gave no specific details as to what it may be.

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The CW President Mark Pedowitz recently confirmed that the network is looking to add another Arrowverse show for the 2020/2021 TV season. Much like Guggenheim, he offered few details, but one can't help but wonder if the two are connected. Then again, Guggenheim tagged @DCComics in his tweet, so perhaps his project will be separate from the Arrowverse altogether.

The mysterious tweet comes weeks before Arrow's eighth and final season begins. The season will contain 10 episodes and will center on the upcoming Arrowverse crossover, "Crisis on Infinite Earths." Guggenheim served as co-showrunner for Arrow's first six seasons.

Meanwhile, Legends of Tomorrow won't return for its fifth season until 2020. However, the show is also going through some changes, with series regulars Brandon Routh, who plays Ray Palmer (The Atom), and Courtney Ford (Nora Darhk) departing at the end of Season 5.

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Returning Tuesday, Oct. 15 at 9 p.m. ET/PT on The CW, Arrow stars Stephen Amell as Oliver Queen, David Ramsey as John Diggle, Rick Gonzalez as Wild Dog, Juliana Harkavy as Black Canary, Katie Cassidy as Black Siren, Katherine McNamara as Mia Smoak, Joseph David-Jones as Connor Hawke and Ben Lewis as William Clayton-Queen.

Returning in 2020 on The CW, DC’s Legends of Tomorrow stars Caity Lotz, Dominic Purcell, Brandon Routh, Nick Zano, Maisie Richardson-Sellers, Tala Ashe, Matt Ryan, Jes Macallan and Courtney Ford.