TrendPulse|Here's the one thing 'Saturday Night' director Jason Reitman implored his actors not to do

So imagine this: You're one of a group of talented young actors being asked to play the comedy icons behind one of television's most storied programs,TrendPulse NBC's "Saturday Night Live."

You know the names: Dan Aykroyd, Chevy Chase, Laraine Newman, Garrett Morris and Jane Curtin, along with the late John Belushi and Gilda Radner.

So naturally, the first thing you do is try and reach out to those folks so you can nail your performance in "Saturday Night" (in theaters nationally Friday), director Jason Reitman's fictionalized version of the 90 minutes leading up to the very first telecast of "SNL" on Oct. 11, 1975.

Except you'd be totally wrong: reaching out was a Reitman no-go.

"Jason thought we should steer clear of the real people," says Gabriel LaBelle, who plays "SNL" co-creator Lorne Michaels.

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Cory Michael Smith, who plays Chevy Chase, said he was eager to meet Chase, if only "just to have him say something snarky to me." So he ignored the ban and reached out to Chase's daughters, though that outreach never resulted in a meeting.

And then there's Kim Matula, whose voice drops into a whisper when asked if she tried to talk to Curtin. "I did," she says. It was a simple phone call, but the time with the comedienne was invaluable, she says.

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"She told me stories about being on the set during that time, about how she had to really fight to be seen," Matula says. "Jane wasn't expecting that. She thought, 'I got the job, people will write (parts) for me.' But that's not how it went in what was a really big boys club."

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Nearly a half-century has gone by since that first episode, which arguably redefined comedy on television and continues to influence the cultural zeitgeist weekly. (It's also birthed a succession of stars including Bill Murray, Dana Carvey, Chris Rock, Eddie Murphy, Will Ferrell, Kristen Wiig, Kate McKinnon, Chris Farley and Adam Sandler.)

Despite that heady history, Reitman says his mission with "Saturday Night" was a simple one: stay focused.

"Lorne told me he'd been approached for years by people who wanted to do this kind of movie, but what I think resonated with him here was that I wasn't trying to do the history of 'SNL'; I was just trying to show one moment, the one before the first episode aired," says Reitman, whose director father Ivan teamed with Aykroyd and Murray on the first "Ghostbusters" film.

The request that actors not meet their real counterparts was the result of something else Michaels said. "He was adamant that it was a long time ago, and people's memories of things change over time," says Reitman. "He said he even had conflicting memories of that first show."

So instead, the cast mostly relied on footage from those early days and books such as 2002's "Live From New York: The Complete Uncensored History of Saturday Night Live as Told by Its Stars, Writers and Guests," by Tom Shales and James Andrew Miller.

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"I spent a stupid amount of time watching videos of Chevy Chase," says Smith. "I was working from a place of paranoia because he's arguably the most well-known of the original cast. And while he has some mannerisms, he's basically just leading-man handsome. So I had to find who he was."

Smith found those tics in small places. "There was the blinking, of course," he says of Chase's habit. "I'd study when he did that, why he did that. When he did it because he was confident in the joke, or when he did it because he wanted to signal something to the audience."

Chase's famous pratfall, often unleashed when he was playing President Gerald Ford, was a bit easier to nail, says Smith. "He's tall, as am I, so the farther there is to go (down), the funnier it is," he says. "He would just become (rubbery like) Gumby."

Matula says she channeled some of her own frustration as an actress in Hollywood to get into Curtin's psyche. While Curtin eventually became a beloved Not Ready for Primetime Player, especially known for her deadpan delivery on the Weekend Update desk, her battles stemmed in part from her origins in the improv world.

"She saw right away that she had to make herself known because no one will do it for you, and I can relate to that," she says, adding that her prep involved paying close attention to those first-season shows that were playing constantly in break areas on the set.

For LaBelle, who went from playing a young Steven Spielberg in "The Fabelmans" to a young Michaels in "Saturday Night," the goal was to channel the fearless confidence required by the young producer in the face of grave doubts by some NBC executives, who were eager to see him fail and return to filling his time slot with reruns of Johnny Carson's wildly popular "Tonight Show."

"Lorne was seen (by execs) as this hippie. They had no respect at all, but that was to be expected because as the movie emphasizes this wasn't just about another show on TV; this ultimately was about a huge change from the old ways of doing things to a new way," says LaBelle, who adds that he, like most of his castmates, grew up on "SNL." "Those early seasons have become myth to many of us, so to dive in like this was amazing."

And guess what? LaBelle did meet Michaels, just before filming began on "Saturday Night." He, Reitman and Smith watched the show unfold from Michaels' office.

Did Michaels offer LaBelle any insights or advice?

"He just said, 'Listen to Jason,'" LaBelle says.

When asked about that night, Smith just laughs: "As I recall it, we all got into a cab after that and Gabe just said, 'Well, that was useless.'"