Theater fans, Gleeks and Ugly Betty mourners (I’m all three), get ready to lose your minds!

On Dec. 9, HBO premieres Six by Sondheim, a brand-new documentary that profiles arguably the greatest composer in contemporary musical theater, Stephen Sondheim. Directed by frequent Sondheim collaborator James Lapine and produced by former Times theater critic Frank Rich, the doc takes a deep look at six of Sondheim’s greatest songs, deconstructed and defined by Sondheim himself.

Among the highlights: “Send in the Clowns” (A Little Night Music), “I’m Still Here” (Follies), “Something’s Coming” (West Side Story), “Being Alive” (Company) and “Sunday” (Sunday in the Park with George).

EW has your extended first look (courtesy of HBO) at the sixth song, Merrily We Roll Along‘s “Opening Doors,” performed in glorious Technicolor by a trio of guest stars: Darren Criss, Jeremy Jordan, and America Ferrera.

The performances are combined with never-before-seen interviews with Sondheim, and the entire documentary is flat-out necessary viewing for anyone who’s a fan of the stage. Even if you’re a Broadway tyro, there’s a certain magic to be had in watching a master composer revisit the inspirations for some of his greatest melodies. The stories are rich and endlessly fascinating, the interviews are intimate, and the experience of watching Sondheim talk (and critique) his own work is simply joyful.