A young girl has penned a heartbreaking letter to Santa asking him to cure her brother's cancer.
Kasie Muir Hart, from Georgia, posted the photo to her Facebook page, showing her seven-year-old daughter Allie's written plea to Santa.
"Sweetest and saddest thing I've ever read," Ms Hart wrote.
"Now, if anyone can find the cure for childhood cancer in the next few weeks, that would he swell. If not a little girl is going to wonder why."
In the letter, Allie admits she's not sure if Santa can follow through with her request, but she thought it's worth asking.
"The gift I really want for Christmas is, well I'm not sure you can do this, but I would like you to try," she wrote.
"I want a cure for cancer because my 13-year-old brother has cancer.
"I have been really good this year, please try."
According to the page, Robert the Great, Allie's 13-year-old brother, was diagnosed with leukaemia in 2010 and since then has endured around 800 doses of chemotherapy and 16 days of radiation.
The post has been shared nearly 148 times and has more than 283 reactions on Facebook.
Commenters reacted with sympathy for little Allie and commended her for her selflessness.
"She has the biggest heart and so, so precious," one commenter said.
"Love her to pieces."