Disneys readying Frozen for Broadway and here, exclusive to The Post, are two of designer Christopher Orams new costumes for Anna.
The green robe this princess of Arendelle wears is a gift from the Hidden Folk, mystical creatures who replace the lovable trolls from the movie. The climbing gear is what she wears to trek up to Queen Elsas ice palace.

As anyone with a daughter knows, Frozen tells the story of two sisters: the aloof Elsa, whose magical powers can freeze the world, and her spunky (unmagical) sister, Anna. When, after years of suppressing her powers, Elsa isolates herself on a faraway glacier, Anna embarks on a journey to find her and bring her home.

Frozen, released in 2013, is the highest grossing animated movie of all time. Thomas Schumacher, the head of the Walt Disney theatrical empire, knew it would work on the stage as soon as he saw a rough cut of it, back in 2012.

I went by myself, late at night, to the screening room and as soon as it was over, I thought, This clearly is a stage musical. The story turns the corner on the songs.

Schumacher says he immediately texted John Lasseter, the head of Disney animation, When do we start on the stage version?

Frozen begins previews next Thursday at Denvers Buell Theatre. The show, said to cost $30 million, will open on Broadway at the St. James Theater in the spring.

Hows it going so far?

Youre asking a man in technical rehearsals with a giant musical how its going? says Schumacher. Are you insane?

Actually, from what Im hearing, its going quite well. All the beloved songs from the movie are in place, as well as 12 new ones, which impressed people whove attended staged readings of the show over the past year.

Schumacher says the score, by husband-and-wife team Robert Lopez and Kristen Anderson-Lopez, has real range to it. It opens with a beautiful orchestral and choral number, then you get pop tunes and Olaf has a vaudeville turn.

Yes, Olaf, the beloved snowman, is in the show, as are the supporting players: Kristoff, the mountain guide; his reindeer, Sven; and Prince Hans, a royal charmer whos not what he seems.

Heading the cast are Caissie Levy as Elsa, Patti Murin as Anna, John Riddle as Hans and Jelani Alladin as Kristoff.

The stage versions of Olaf and Sven look like they do in the movie. But director Michael Grandage and Oram have come up with plenty of twists, some downright eye-popping, on Arendelles castle, the frozen forest and the ice palace.

The sets are enormous so big that the owners of the St. James have blown out the theaters back wall to create a bigger stage.

Were not doing an exact copy of the movie, says Schumacher. We evoke the movie, but were creating something original for the stage.

Frozen, the musical, runs about 20 minutes longer than the movie, which gives the creators time to dig a little deeper into the characters and their predicaments.

Were not doing an exact copy of the movie. We evoke the movie, but were creating something original for the stage.

Whats going through Annas head when Hans tells her he never loved her? says Schumacher. What is Elsa thinking as shes being coronated? Kristen and Bobby [who also wrote the films songs] know this material so well, they can go deep into it.

Even Olaf, a life-size puppet operated by the actor Greg Hildreth, gets a second song in the musical.

So far, the only iceberg along the way was the dismissal of the shows original director, Alex Timbers. He was long a Disney favorite, having co-directed Broadways Peter and the Starcatcher on Broadway. But Disney, sources say, had doubts about his ability to command a show the size of Frozen.

The decision to hire Grandage seemed odd at first, since the British director is best known for staging such plays as Frost/Nixon and Red. He directed a revival of Evita in London and New York, but was never thought of as a director of musicals.

But Schumacher admired his work at Glyndebourne, the fabled opera festival in England, where Grandage staged Billy Budd and The Marriage of Figaro. Hes also directed plenty of Shakespeare plays, which, like musicals, have large casts and sprawling sets.

Michael brings the heft of classical theater to the show, says Schumacher. There are times when I look at this production and think it could be done at the Old Globe.

Disneys had a good run on Broadway with Beauty and the Beast, The Lion King and Aida. There were a few stumbles The Little Mermaid and Tarzan but Aladdin is a big, crowd-pleasing hit at the New Amsterdam.

Frozen seems poised to join the list of winners.

One thing no ones messing with: Let It Go. Its the big turning point in the movie and, powerfully sung by Levy, brings the curtain down on the first act, no doubt planting itself in the minds of a new generation of theatergoers.