'Let It Go' is the hit song that keeps on getting better.

Four-year-old Kaelyn, her three-month-old brother and their mother got trapped in an elevator last week in Reading, Massachusetts.

Firefighters who arrived on the scene placed a ladder into the elevator, which freaked out Kaelyn, so the firemen did what any quick-thinking rescue workers would: to calm her down, they played the smash Disney song on one of their phones and then began to sing along with it.

The plan worked -- Kaelyn did indeed calm down and she, her brother and mother were all rescued in about 30 minutes.

One of the firefighters, who also has a young child, said, “I don't like to admit to it to, but it just gets stuck in your, kind of a catchy tune."

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