When the actress who played Princess Anna in the Disney movie 'Frozen' heard about a young fan's illness, she just couldn't "Let it Go."

All it took was one phone call from Kristen Bell to make the girl's day.

Six-year-old Avery Huffman has an inoperable brain tumor, and her family has been documenting her illness and treatment online.

Somehow, word got to the A-list actress, and she called to leave a voicemail for the little girl as Avery's favorite character, Anna from 'Frozen.'

In the voicemail, which ABC confirmed came from Bell, she says, "This is Princess Anna of Arendelle. I just wanted to call and say, 'Hello.'"

She goes on to say her famous sister Elsa, "Has decided to crown you as an honorary princess of Arendelle." Bell adds, "I think you'll make a great princess."

From the look on Avery's face, she was blown away - and so were her parents, who commented on her CaringBridge page that they've watched the video of their daughter listening to Bell's voicemail dozens of times, just to hear her giggle and see her smile.

(WATCH Avery's reaction in the video below) - Photo: Kristen Bell Facebook

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