How the hell are you going to cast this thing?'

And I was really intimidated.'"

Hopper Stone/Sony

He credits casting director John Papsidera for having a “particular gift for finding talent.”

Gilda Radner (Ella Hunt), Jane Curtain (Kim Matula), Dick Ebersol (Cooper Hoffman), Rosie Shuster (Rachel Sennott), Garrett Morris (Lamorne Morris), Alan Zweibel (Josh Brener) and Lorne Michaels (Gabriel LaBelle) in SATURDAY NIGHT.

‘Saturday Night’.Hopper Stone/Sony

It was a “no-brainer” thatLamorne Morrisshould play Garrett Morris.

But one cast member of that inaugural season proved especially difficult.

“[Dan] Aykroydwas almost impossible,” Reitman admits.

Dylan O’Brien as Dan Aykroyd in Saturday Night

Dylan O’Brien as Dan Aykroyd in ‘Saturday Night’; Aykroyd on ‘Saturday Night Live’.Sony; Getty

“Dylan [O’Brien]came very late in the process, and it was, thank God.

I mean, that was a big moment.

“Dylan is so good in the movie.

Gabriel LaBelle as Lorne Michaels in Saturday Night

Gabriel LaBelle as Lorne Michaels in ‘Saturday Night’; Lorne Michaels on the set of ‘Saturday Night Live’.Sony; Getty

But he admits one of the roles was more daunting than the other.

And he’s right there he’s right there, he’s watching you.

“I hadn’t been validated yet as an artist or an adult.

Listen to Reitman and LaBelle’s full interview onThe Awardistpodcast, below.

Saturday Nightis in theaters now.