BEVERLY HILLS—Robert and Richard Sherman aren’t exactly household names but odds are that at least a couple of members of any household can recite a Sherman brothers song. The duo, famous for contributing to classic Disney films like Mary Poppins and The Jungle Book, are highly respected in the canon of great songwriters, having won two Academy Awards while garnering seven other nominations.

So when it came time to cast young versions of the brothers for Disney’s Saving Mr. Banks—the film, opening December 20, is based on Walt Disney’s battle to acquire the rights to the novel Mary Poppins—director John Lee Hancock found in Jason Schwartz­man and B. J. Novak two names that aren’t instantly recognizable to most. Like the Shermans’, though, their work is ubiquitous.

Both are known for their comedic acting (Schwartzman as a fixture in the films of Wes Anderson, and Novak as Ryan in TV’s The Office), but they’ve also branched out easily into other areas of show business. Schwartzman, who plays the more musically inclined Sherman, Richard, was the drummer and cofounder of the band Phantom Planet (whose “California” became the theme song to The O.C.) before moving on to a solo project, Coconut Records, and churning out popular tracks like “Nighttiming” and “West Coast”.

Novak is a Harvard grad who has also worked as a writer and director, notably on TV’s The Office and The Mindy Project. His collection of comedic short fiction is set to hit bookshelves in early 2014.

So why, with so much else on their plates, did they take on these relatively small roles? For both actors it was a trip down memory lane to source material they first experienced as children. “We talked about this last night,” Novak says during a hotel news conference. “Because I thought I had seen Mary Poppins. I knew all the songs; I knew all the characters. I had absorbed it without ever having seen it. The film itself is so much odder than we remember, and so much more complicated, let alone the story and context of it. Growing up, these Disney songs, the Sherman brothers songs especially, you just feel like they came from heaven fully formed. And that was so interesting about making this movie, seeing all the drafts and the scenes that I never knew were even there.”

“It meant a lot to me, this movie, growing up,” Schwartzman adds at the same conference. “I saw it a lot of times and I knew most of the songs from the movie.…It’s funny just how much, when you’re little, a movie can affect you. It was only [when we were on set] that it occurred to me that Mary Poppins was shot in Burbank, because I experienced it as a young person thinking it was made in England, and it was only recently that I realized that it was all made up. It’s like how there’s photos of guys smoking cigarettes by [the mechanical shark from] Jaws. I wish I hadn’t ever seen those photos, and I wish I’d never seen Cherry Tree Lane on Burbank Boulevard. It means a lot to me, this movie. I loved it very much.”