The celebrated actress also opened up about working with Riz Ahmed on their new film, 'Encounter.'
Spencer spoke with ET's Matt Cohen on Tuesday, at the Los Angeles premiere of her new sci-fi drama Encounter, and was asked about her outspoken appreciation for the Kevin Costner-led series.
"Oh my gosh! Who's not [a fan]?" Spencer marveled when asked about some of the comments she's made, including on social media, about the show. "It's amazing."
Season four of Yellowstone kicked off Nov. 7 with the first two episodes airing back-to-back -- something Spencer clearly has some strong feelings about.
"Since they gave us two episodes for the premiere opener I'm like, 'Does that mean you guys made 11 episodes for this season, or are we really counting down?'" she added, referring to the show's now-traditional 10-episode runs for their last two seasons.
While she isn't planning on trying to get cast on the show, she does want to see where the magic happens.
"I'm just gonna find myself out there on their set one day," Spencer said with a laugh. "Wearing a mask though, guys, I will be masked up. But I'm coming to visit."
Spencer would likely be met with open arms -- at least by series star Costner, who has worked with the Oscar-winner on multiple projects in the past, including the celebrated Hidden Figures and the 2014 family drama Black or White.
As for Spencer's own projects, her new film Encounter sees Riz Ahmed as war veteran Malik Kahn, who believes an extraterrestrial threat is invading earth. He decides he needs to keep his two kids safe by taking them from his ex-girlfriend's house and seeking refuge from the alien menace he's having a hard time convincing people is real.
Spencer stars as Hattie, Malik's parole officer who is leading a group of authorities bent on stopping Malik from accomplishing what he believes is the most important mission of his life with his sons.
"Riz is one of the greatest actors of his generation," Spencer said of the 39-year-old star, who was nominated for an Oscar earlier this year for his performance in Sound of Metal.
"He's just brilliant. He's such a hard worker, such a strong work ethic, and just truly an amazing artist," she continued. "To work alongside him has been such an honor."
Encounter hits theaters Dec. 3, and is available for streaming on Amazon Prime Video on Dec. 10.
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