It's a tradition to toast the first and lost shot on all of his movies, director Stephen Spielberg explains to the cast and crew in a new West Side Story featurette—take a look above. "And I just want to say we have actually been in production on this for months," he adds, referring to the music and dance rehearsals leading up to the first day of filming.

Watch the video above for a few new glimpses of that choreography and strains of the score, including tidbits of "Tonight" and "America," and "A Boy Like That."

The new film adaptation of the Leonard Bernstein, Stephen Sondheim, and Arthur Laurents musical arrives in theatres December 10 starring Rachel Zegler as Maria, Ansel Elgort as Tony, Ariana DeBose as Anita, David Alvarez as Bernardo, Josh Andrés Rivera as Chino, Tony nominee Brian d’Arcy James as Officer Krupke, Corey Stoll as Lieutenant Schrank, and EGOT winner and star of the original 1961 film Rita Moreno in the newly created role of Valentina.

New Teaser "Falling" Drops for West Side Story

Tony Award winner Tony Kushner supplies the screenplay for the film, featuring choreography by Tony winner Justin Peck. The music team includes Tony-winning composer Jeanine Tesori and Los Angeles Philharmonic Music Director Gustavo Dudamel.