(CNN) Exactly how secretive is Marvel Studios when guarding the plot details of their superhero films, even from name actors making cameos? CNN put the question to Yvette Nicole Brown, who revealed that she wasn't even sure which "Avengers" film she'd ultimately end up appearing in -- and didn't find out until after she bought a ticket.

Yvette Nicole Brown arrives for the premiere of Netflix's "Dear White People" Season 3 at Regal Cinemas LA Live in Los Angeles on August 1, 2019. (Photo by LISA O'CONNOR / AFP) (Photo credit should read LISA O'CONNOR/AFP/Getty Images)

During her stint starring on the cult-favorite sitcom "Community," Brown worked closely with Joe and Anthony Russo, who served as executive producers on the show before earning their superhero cred in the Marvel Cinematic Universe . Fellow cast members like Danny Pudi and Jim Rash had been previously recruited by the Russos for cameo roles in Marvel films, and Brown -- also well known for passionate film and TV superfandom on social media and various talk shows -- was just waiting for her own invitation into the MCU.

As the Russos were in the thick of filming "Avengers: Infinity War" and "Avengers: Endgame" back-to-back, Brown's call finally came in October of 2017. "I was on the set of 'The Mayor' for ABC and I got a text from Joe Russo," she recalled. "He said, 'Hey, what are you doing two weeks from now?' And I called him -- I didn't even text back. I called him! 'Is it? Is this it?' He said, 'This is it. It's your turn. This is the call.'

Brown immediately called her TV series' showrunner.

"I was like, 'I need next week off, because I've got to do this thing!' And luckily, because Marvel is also under the Disney-ABC umbrella, they worked everything out and I was able to go to Atlanta for a couple of days and knock it out," she said.

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