Kristen Bell has helped a young Frozen fan in the most magical way possible.

Four-year-old Avery Huffman was diagnosed with an inoperable brain tumour on June 30th.

In the month since her diagnosis, her father Brandon has chronicled Avery’s treatment online.

“Despite the last 3.5 weeks being a nightmare for our family, especially for Avery, there are some days where you’re just able to forget, if even for just a little bit, the awful battle she’s doing through.” he wrote in a blog post yesterday.

One of those moments was on Monday, a day Brandon described as a rollercoaster.

“Like roughly 93% of all little girls in the United States, Avery loved the movie Frozen. We’ve probably watched or heard it over 200 times.” he wrote.

“I’ve sang my share of duets of ‘Love is an Open Door’ with Avery while watching numerous performances of Let it Go, Do You Want To Build A Snowman and For the First Time in Forever.”

Princess Anna was Avery’s favourite character from Frozen, and a friend of Brandon’s arranged for Kristen Bell to call Avery, pretending to be Anna.

According to her dad, it made her day/week/life.

“Avery couldn’t stop talking about it and was so excited to have her sisters and brother hear it.” he wrote.

Watch the special moment here: 

Video via Brandon Huffman

Are your kids Frozen fans? 

Want more? Try these… 

Because we can’t Let it Go… The Frozen Fever trailer is finally here.

9 epic ‘Let it Go’ covers to celebrate Frozen’s win at the Oscars.

Little girl, possibly possessed, tries to convince dad to shoplift Frozen doll.