How can you rekindle the magic of Christmas for an audience of seen-it-all-before New Yorkers? Well, it helps if you unleash the lullaby rhythms of the Welsh poet and author Dylan Thomas, whose wide-eyed incantations have the power to disarm and delight.

“All the Christmases roll down the hill toward the Welsh speaking sea, like a snowball whiter and bigger and rounder, like a cold and headlong moon bundling down the sky that was our street,” Thomas writes, in language so vivid you’ll be powerless to resist.

Not everyone, it’s fair to say, earnestly enjoy Christmas or the carols that come with it. In fact, secretly there are quite a few New Yorkers who might vote to skip Christmas altogether, and especially all the songs, if given the option. Irish Rep director Charlotte Moore knows this, and so she brings out the big guns to head off the cynics.

A Child’s Christmas in Wales, which opened last week at the Rep, succeeds as well as it does because of the talents Moore has assembled. Chief among them is the musical direction by John Bell, which is truly note perfect from beginning to end.

Playing both traditional and contemporary Christmas music, Bell manages to elevate the show’s familiar material, and in fact the whole experience, in ways you can’t anticipate before the curtain goes up.

Remembered music and remembered voices have the power to break the heart, and in between all the familiar carols, Bell somehow manages to somehow evoke all the Christmases you’ve known by playing just a few notes on a baby grand piano.

It’s quite a trick that, and just the kind of wizardry that brings this surprisingly disarming show to life. ‘Tis the season to reflect on the past and to contemplate the year to come, after all, and where better really than in the company of a group of talented singers and musicians?

But in between all the carols and the music something else is allowed to emerge -- the notion that ultimately Christmas isn’t about songs or big dinners or presents or even the nativity. It’s really about all the people you love dearly and those who love you, and if you’re very lucky indeed there will be more rather than less of them around your table this year.

So simple human warmth is the powerful antidote to the endless corporate takeover that is threatening to devour what remains of the holiday, and it’s why we should be thankful for directors like Moore who insist on finding what’s best in all of us, in the belief that it’s more than enough.

Christmas means the most to the young, but it can still have the power to delight the young at heart too.  In this way the Rep’s cast, which includes Broadway stalwarts like relative newcomers Ashley Robinson and Kerry Conte, more than match Simon Jones, Martin Vidnovic and Victoria Mallory.

Robinson and Jones in particular have the kind of mischievous twinkle that compliments Thomas’ playful source material, and they bring a levity and sense of fun to the whole evening that never diminishes.

A sad song’s best for winter, but the show’s songs range from solemn to silly, and Thomas’ poetry and Bells thoughtful arrangements really lift this show into orbit.

There are some turkeys -- seasonal songs like C. Frank Horn’s “Miss Fogarty's Christmas Cake” aren’t really as lyrically inventive or even as funny as they let on, and while this number lent an Irish note to a Welsh celebration, it could just as easily be retired without incident.

The lighting design needed a few extra tweaks as the show got ready for opening night. Green laser starlight made a good impression on the theater’s backdrop, but it also landed on the faces of some of the actors from time to time, making you worry for their vision. Rousing choruses were interrupted by washes of light that came on just a millisecond too soon or too late.

Otherwise, though, A Child’s Christmas in Wales is a reminder of what the Irish Repertory Theatre does best -- it brings together the top theater professionals in New York to put on a show that ends up creatively outgunning every off-Broadway house in the city, time after time.

The run ends on January 2. For tickets and showtimes call 212-727-2739.