'Star Wars' Cast on the Importance of Rey, Finn and Poe's Adventure in 'Rise of Skywalker' (Exclusive) 

The Skywalker saga is coming to an end -- but not without one last adventure.

Another Star Wars trilogy will come to an end with The Rise of Skywalker -- but first, we'll get the trio adventure we've all been waiting for. 

ET's Ash Crossan sat down with the movie's cast at the Rise of Skywalker Los Angeles press day on Monday, where they opened up about Rey (Daisy Ridley), Finn (John Boyega) and Poe (Oscar Isaac) finally getting together in the upcoming film. As Boyega put it, "You're not in Star Wars until people see you as a trio." 

"That was important in this one, for me, that we were together to just show that chemistry and show what I've always enjoyed about Star Wars, which is the connection between people," he shared. 

"I was just happy to get out of the cockpit for a little while," Isaac joked. "Finally! I've been sequestered in space by myself for a while, so for me, that was one of the most exciting things, when I read the script, the three of us were gonna actually get together."

The actor continued: "You get to see the dynamic between the three of us, and I think the natural chemistry we all share together and also the way JJ [Abrams] let us play within those scenes and shot those scenes. There was a lot of... improvisation and excitement and talking over one another. So, you felt that we were connected."

It's not just seeing their characters together onscreen that was important to Boyega, however. As he shared with fans on Twitter on Saturday, he's looking forward to spending much-needed quality time with Isaac on the press tour. He bared his soul and shared his feelings in a hilarious "letter" to his co-star, and posted the video to the social media platform. 

"He has his own film crew following him," Isaac cracked -- but it was no laughing matter to Boyega. 

"As the ambassador of Star Wars fans, I'm here to make sure the press tour goes well and we have a lot of fun with each other and I think it's cool to be able to show that side," Boyega explained. "While I was in Berlin, I just saw a table that looked very old school, so I told my team, 'Cool. This would be a great chance to write a little [letter].'" 

"And he got the letter," he happily confirmed. 

"It was a beautiful letter," Isaac raved. 

The Rise of Skywalker -- the final episode of the nine-part Skywalker saga -- follows the Resistance as they face the First Order once more, and the end of the ancient conflict between the Jedi and the Sith. In addition to Boyega, Ridley and Isaac, the film's ensemble cast also includes Mark Hamill, Adam Driver, Anthony Daniels, Domhnall Gleeson, Richard E. Grant, Lupita Nyong'o, Joonas Suotamo, Kelly Marie Tran, Ian McDiarmid, Billy Dee Williams and the late Carrie Fisher. 

Keri Russell and Naomi Ackie also join the cast this go-around; Russell couldn't believe it when she finally set foot on set.

"There was this moment when I saw this huge group of stormtroopers go past, like, in the uniforms, in formation and I was like, 'Oh my god. I'm in it. I'm in it. I'm really in it,'" she recalled. "That was really cool!"

Ackie is still getting used to being part of the team -- but Ridley's got some plans for the press tour. "We got a big amount of travel to do, so I think the next few weeks will feel like a little celebration," she shared. 

Star Wars: The Rise of Skywalker hits theaters on Dec. 20.