While we found out pretty early on that Kurt Russell was playing Ego the Living Planet, the MCU's version of Peter Quill's father, we were left guessing who a pair of heavy hitters — Sylvester Stallone and Michael Rosenbaum — were playing in Marvel's latest foray into the cosmic side of the universe.

Up Next: Rosenbaum Reflects On His Failed Star-Lord Audition

Rosenbaum — who played Martinex in the movie, a member of the original Guardians team in the comic books — revealed in a recent interview with The Hollywood Reporter that even though he had a relatively minor role, he knew the entire plot line of the movie well in advance.

"I got the whole script. It was watermarked with my name. I knew Yondu [Michael Rooker] died before we shot it," Rosenbaum reflected. "I was sitting at the premiere with Michael Rooker and I could tell he was choking up at the end … it really says something when a man can get emotional about his own work."

With Martinex now in the universe — and the fact that Stallone played Stakar Ogord, another one of the original Guardians — Marvel is digging deep into the cosmic side of comic lore, and that fact alone should excite fans for the future of the MCU.

Set to the backdrop of ‘Awesome Mixtape #2,’ Marvel’s Guardians of the Galaxy Vol. 2 continues the team’s adventures as they traverse the outer reaches of the cosmos. The Guardians must fight to keep their newfound family together as they unravel the mysteries of Peter Quill’s true parentage. Old foes become new allies and fan-favorite characters from the classic comics will come to our heroes’ aid as the Marvel cinematic universe continues to expand.

Guardians of the Galaxy Vol. 2 is written and directed by James Gunn (Slither). The film marks the return of the original Guardians, including Chris Pratt (Jurassic World) as Peter Quill/Star-Lord; Zoe Saldana (Star Trek Into Darkness) as Gamora; Dave Bautista (Spectre) as Drax; Vin Diesel (Furious 7) as the voice of Groot; Bradley Cooper (American Sniper) as the voice of Rocket; Michael Rooker (Jumper) as Yondu; Karen Gillan (The Big Short) as Nebula; and Sean Gunn (Gilmore Girls) as Kraglin. New cast members include Pom Klementieff (Oldboy), Elizabeth Debicki (The Great Gatsby, Everest), Chris Sullivan (The Knick, The Drop) and Kurt Russell (The Hateful Eight, The Thing).

Guardians of the Galaxy Vol. 2 is in theaters now. Spider-Man: Homecoming lands on July 7, 2017, followed by Thor: Ragnarok on November 3, 2017. After that Black Panther debuts on February 16, 2018, while Avengers: Infinity War hits theaters on May 4, 2018. Ant-Man and the Wasp is slated for July 6, 2018, followed by Captain Marvel on March 8, 2019.