When Season 5 of Marvel's Agents of S.H.I.E.L.D. was headed to its conclusion, many fans believed they were watching the end of the Marvel Cinematic Universe's first television series. It turns out the fans were not alone, as the cast of the show thought that the Season 5 finale would be the end as well.

Clark Gregg, who stars as Agent Phil Coulson on Marvel's Agents of S.H.I.E.L.D. and will return to the big screen for the upcoming MCU movie Captain Marvel, told ET Online that they were ready to say goodbye.

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"We had this really wonderful end of season five -- the [season finale] episode was even called 'The End' -- and we had reason to believe that we were done," Coulson said. "We’d had these wonderful five seasons and a very tight family, and it was very, very sad. And then they called everyone up and said, we’re actually gonna do two more short, 13-episode seasons, which is really the number we thought we always could do best at."

With the show's unexpected renewal for two more, relatively short 13-episode seasons, it seems like the cast and crew behind Agents of S.H.I.E.L.D. got exactly what they wanted, including the chance to tell more concise stories without much filler.

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When the next season of Marvel's Agents of S.H.I.E.L.D. premieres this summer, Mack (Henry Simmons) has taken over the leadership role of S.H.I.E.L.D., and the first trailer for the upcoming season teased a few massive spoilers.

With two seasons to go, this one will see the split team as they continue their separate missions and storylines and will likely all culminate in or close to Season 7 with everyone coming back together for an  explosive climactic reunion.. Gregg said that he is excited to see what Jed and Mo Whedon came up with.

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While talking about how he's looking forwards to seeing what showrunners Jed and Mo Whedon come up with, Gregg also said that he would play a surprising role in Season 6.

"I don’t know what people are going to think, I do not know," Gregg said. "That’s what I like about the show. They have a great bravery in terms of throwing out all the rules and taking risks. And they’ve really taken one this year."

Agents of S.H.I.E.L.D. is set to return for its sixth season in July 2019 on ABC with 13 new episodes. The series stars Ming-Na Wen, Chloe Bennet, Henry Simmons, Iain De Caestecker, Natalia Cordova-Buckley and Elizabeth Henstridge.