VIDEO: Idina Menzel & Cast of IF/THEN Lead FROZEN Singalong on GMA

Thousands joined together for an epic coast-to-coast "Frozen" singalong live today on "Good Morning America," from Tony Award-winning singer Idina Menzel and the cast of her highly anticipated new Broadway musical If/Then, to the New York City Children's Chorus, to fans who gathered in Times Square, and viewers around the country who sent in their own heartwarming renditions. Check out the video!

Menzel and the cast of 'If/Then' including Anthony Rapp, James Snyder and Jenn Collela lead the charge kicking off the extravaganza, followed by three young soloists dressed in their finest "Frozen"-themed attire. Times Square was overwhelmed by the vocals from military troops, the families that are huge "Frozen" fans and even a few Starbucks employees.

Jack Hanna took part singing with one of his penguins at the "GMA" anchor desk, as did David Muir in the "World News" studio, not to mention Avenue Q, Kelly Ripa and Michael Strahan in their ABC studio uptown and the Liberty Corner Elementary School singing along with the Skyliners Synchronized Skating Team in Bryant Park.

"Frozen" has become a box office behemoth since its November release, but it has also become a musical phenomenon, with its song "Let It Go" striking a chord with millions of people around the world.

In an interview featured on today's GMA, Idina Menzel, the powerhouse singer Tony Award-winning singer behind the song's original vocals, said she's surprised by the way the song has caught on. "I'm surprised at how big and popular it is, but I as a woman I completely relate to this character and I relate to the idea of a woman or girl and having power and not knowing what to do with it and being afraid of your own power and learning to harness that and own that," she said.

The film has earned two Academy Awards nominations in the Original Song and Animated Feature Film categories.

Menzel, who will perform the song at The Academy Awards ceremony on Sunday, acknowledged she was nervous for the upcoming performance, adding: "Nerves are good. They keep you alive. This is a dream come true. I've watched many people I admire perform and just to be nominated and a part of it is really surreal for me and I'm just having fun with it."