Leave it to director Steven Soderbergh and composer Thomas Newman to go retro ’60s with the music for their fourth collaboration, “Let Them All Talk.”

Accompanying Meryl Streep, Candice Bergen, Dianne Wiest and the rest of Soderbergh’s cast crossing the Atlantic on the Queen Mary 2 is a jazz score that might easily have been penned by John Barry (“The Knack”), Neal Hefti (“The Odd Couple”) or Henry Mancini (“The Pink Panther”).

“Steven genuinely loves that kind of music,” Newman tells Variety. “It was fun to be doing something so different, so outspoken. I’m usually more into the sensuality of how music hits image and can shape and structure things. This was a lot of jazz waltzes.”

Soderbergh contacted Newman while the composer was finishing his “1917” score in London a year ago. They had previously collaborated on “Erin Brockovich,” “Side Effects” and “The Good German,” the last of which earned Newman one of his 15 Oscar nominations.

Newman called on his longtime collaborator, keyboardist John Beasley, to arrange the score and perform it with his MONK’estra big band. Beasley’s Hammond B3 organ — a sound familiar to ’60s jazz buffs — joins guitarist George Doering, flutist Steve Tavaglione, drummer Peter Erskine, bassist Benjamin Shepherd and percussionist Dan Greco as the core ensemble for most of the score.

The lighthearted, effervescent tone is heightened by the presence of wordless voices (“processed samples,” Newman reveals). “There’s something spritzy and carbonated about it, that Swingle Singers kind of sound,” referring to the ’60s vocal group famous for their vocalized versions of classical pieces.

“It all happened very quickly,” Beasley confirms. “It was like a master class times two, sitting with Tom. He had these ideas about tempo and grooves, I’d start building the tracks, and the next day he’d come in with these incredible melodies. Because I made the mockups with keyboards, it was natural for me to do the orchestration and have my guys play it.”

In addition to Beasley’s 15-piece big band, there’s also a cushiony string section, both recorded at Fox’s Newman stage in January and February, prior to the pandemic that ended virtually all orchestral recordings for the next several months.

The 1960s influenced the sound of the score in other ways, Beasley adds: “I wanted to get that roomy, vintage studio-orchestra sound from back then.”

Newman and Beasley have been working together since the movie “Career Opportunities” in 1991, with Beasley mostly playing keyboards and synthesizers and adding percussion sounds.

Soderbergh resisted a traditional underscore, Newman reports, so the total amount of music in the film is only about 20 minutes. “He didn’t want music doing what, typically, film music would do. He just wanted it to be outgoing, to carry with it a kind of breeziness. It went with Meryl Streep’s sunglasses and Candice Bergen’s cowboy hat. The cruise [setting] played into that vibe and style.”

The composer praised the director for “wanting you to be creatively expressive. He feels it’s in the interest of the film to let his creative people be that way.”

Beasley, coincidentally, is currently up for four Grammys in the jazz and arranging categories; Newman’s also nominated for composing the “1917” score.