The ninth and final episode Watchmen Season 1 -- which is due to air on HBO this Sunday -- promises to be the premium drama series' longest installment yet.

The Watchmen finale -- titled, "See How They Fly" -- is noticeably longer than the previous eight episodes, clocking it at a whopping 67 minutes. As such, it appears the series is preparing to conclude its first (and perhaps only) season in a major way.

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For reference, Watchmen's longest episode to date is its most recent one, "A God Walks into Abar," which clocks in at 63 minutes. Prior to Episode 8's release, the longest installment of Watchmen was a tie between its premiere episode, "It's Summer and We're Running Out of Ice," and its sixth episode, "The Extraordinary Being" -- both of which are 61 minutes in length. Meanwhile, the series' shortest episode is its fourth, "If You Don't Like My Story, Write Your Own," at 52 minutes.

As such, the vast majority of Watchmen's episodes have run between 52 minutes and 61 minutes. Even when factoring in the most recent episode's 63 minute runtime, the series' average episode length comes in at just under 58 minutes. At 67 minutes, "See How They Fly" goes beyond that average by a considerable margin.

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Developed by Damon Lindelof, HBO's Watchmen stars Jeremy Irons, Regina King, Don Johnson, Tim Blake Nelson, Jean Smart, Louis Gossett Jr., Yahya Abdul-Mateen II, Tom Mison, James Wolk, Adelaide Clemens, Andrew Howard, Frances Fisher, Jacob Ming-Trent, Sara Vickers, Dylan Schombing, Lily Rose Smith and Adelynn Spoon. The season finale airs Sunday at 9 p.m. ET/PT.