Grown adults were grinning like awestruck children as the legendary filmmaker Steven Spielberg and composer John Williams discussed their unparalleled 50-year collaboration during an American Cinematheque celebration of the duo at the Writers Guild of America Theater in Beverly Hills on Thursday night (Jan. 12) — and that was before Williams, 90, thrilled the crowd, and surprised Spielberg, by rescinding his prior declaration that he would retire from film scoring after his latest project with Spielberg, The Fabelmans and then one more Indiana Jones film.

“Steven is a lot of things,” Williams said in response to a question from veteran music journalist Jon Burlingame about packing it in. “He’s a director, he’s a producer, he’s a studio head, he’s a writer, he’s a philanthropist, he’s an educator. One thing he isn’t is a man you can say ‘no’ to.” After an eruption of applause from the audience, Williams noted that he knew Spielberg’s late father, Arnold, who worked at Spielberg’s Shoah Foundation until he was 100. “So I’ve got 10 more years to go. I’ll stick around for a while!” He added, “Also, you can’t ‘retire’ from music. It’s like breathing. It’s your life. It’s my life. A day without music is a mistake.”

Spielberg, who was visibly taken aback at Williams’ change of plans, cracked, “I’d better get to work to find out what the hell I’m doing next!”

Between carefully curated clips from some of the 29 films they have teamed up for, Spielberg and Williams discussed how they met (a Universal executive suggested that Spielberg, a young director in need of a composer, and Williams, an up-and-coming composer, meet for lunch), how they work together (Williams rarely accepts Spielberg’s offer to read a script prior to production, opting instead to wait until it’s done, at which points, Spielberg says, “John sees the movie, then we sit down the next day, and we just start discussing where there should or should not be music”) and they spoke about the role that music plays in the movies, generally, and in their movies, specifically.

“Music is probably older than language,” Williams asserted. “It is a very important thing in all of us — when we’re grieving, when we’re happy. We don’t know why. It’s unknowable.” As for how he determines if a film scene does or does not require musical accompaniment? “In the end, the film tells us, if we pay attention enough. It’s mainly intuitive.” Spielberg paid tribute Williams’ contributions by stating, “I tell a story, and then John retells the story musically.”

Spielberg was aware of Williams’ work before they met, having worn out his copy of the vinyl soundtrack for The Reivers, a 1969 film that Williams had scored. When they first sat down together, Spielberg — a student of film history and film music whose late mother, Leah, was a classical pianist — “seemed to know more about film music than I did,” Williams realized, so Williams agreed to work with him on Sugarland Express.

They began on that film in 1972 — it was released in 1974, and then a year later came Jaws, the first of their truly immortal collaborations. Of Williams’ simple but haunting score for that thriller, Spielberg admitted to Williams, “I was scared when you first played it for me on the piano. I didn’t know you that well. I thought you were pulling my leg.” But Williams had hit on something: “You could play it very softly or very quickly, or soft or loud, so you could kind of manipulate an audience,” he explained.

Music was a central part of the plot of 1977’s Close Encounters of the Third Kind, with its five-note signature tune — arrived at after 100 permutations were considered — representing a means of communication between humans and aliens. Discussing 1981’s Raiders of the Lost Ark and 1982’s E.T., with their iconic themes, Williams said to Spielberg, “You and I have always been talking about tempo on films,” observing that the addition of music can make four minutes of screen time feel like two.

Both men faced two massive challenges in 1993: Jurassic Park and Schindler’s List. Spielberg marveled that Williams had scored the former without the dinosaurs having already been added via visual effects, and yet still captured musically the childlike sense of wonder of the characters, who were, at least at that time, played by actors who were “looking up at nothing.” Williams scored Jurassic Park while Spielberg began work on Schindler’s, marking one of the few times that the filmmaker wasn’t present for a Williams scoring session.

As for the role that music would play in Schindler’s? “I really didn’t have a plan,” Spielberg admits. When he finally showed a cut of the film to Williams, Williams was so moved that he was unable to speak for several minutes. “Then,” Williams recounted, “I said, ‘Steven, you need a better composer than I to score this film.’ And he said, ‘I know, but they’re all dead.’” Williams’ violin-centric score ended up being one of his masterpieces, as the film is one of Spielberg’s.

Sometimes, the duo explained, less is actually more when it comes to music in films. They said they never even considered incorporating music into the famous opening sequence of 1998’s Saving Private Ryan, but decided to employ the trumpet and low strings to stir emotion in later scenes, most famously in the hushed and reverential choral finale. “Musically, it honors all of the veterans, both today and yesterday,” Spielberg said of Williams’ composition for that film, “and it’s why the military is always asking if they can play this score.”

The jazzy main title sequence of 2002’s Catch Me If You Can took Williams back to his roots as a jazz pianist in the 1950s, and Spielberg’s as a jazz aficionado who hung out at jazz clubs while a student at Long Beach State in the 1960s. The recording of Williams’ score for 2012’s Lincoln, which was inspired by 19th century American music, with trumpets at the fore, moved Spielberg and Williams — both students of history — to tears. But for Spielberg, who lost both of his parents in recent years, and for Williams, who had known both of them, The Fabelmans was an undertaking unlike any other.

“For me,” Spielberg professed, “it was the most private and personal experience of my whole career.” Speaking on what would have been Spielberg’s mother’s 103rd birthday, Williams said of his score — which has already been nominated for Golden Globe and Critics Choice awards — “I hope it is worthy of them,” to which Spielberg quickly responded, “Oh, it is.”

Asked to sum up their half-century of making movie magic together, Williams said of Spielberg, “I’ve enjoyed his company and the pleasure and the gift of his inspiration. Can a muse be a man? He’s certainly been a muse for me.” Spielberg, for his part, said that working with Williams — “Johnny,” as he calls him — had been like a ideal marriage. “I don’t think we’ve ever had a disagreement,” he volunteered, before adding with a chuckle, “I mean, what am I going to do? Sit down and write the music myself?” And, he added, prompting Williams to choke up, “In the art form that we’ve both chosen, he has been the most steadfast brother and collaborator that I’ve ever had in my life. And that’s how I would sum up how much I love you.”

This article originally appeared on The Hollywood Reporter.