A Boston woman whose daughter recently died of cancer says Justin Bieber is the "sweetest, kindest person" for visiting the girl shortly before her death.

Pam Drew says Bieber left a lasting impression on 10-year-old Karlee, after visiting with her at a concert of his last May.

"She has since passed and I need to make sure you know how much you made her happy," Drew wrote in a post on Bieber's Facebook page.

Karlee Drew died on Saturday, after a long battle with acute myeloid leukemia.

Drew said Bieber's music was one of the last sounds her daughter responded to before she died.

"On one of her last days she was unresponsive to all except when the paramedic had put your song on his phone," Drew wrote. "My daughter's head bounced up and down a few times and she smiled."

Bieber has not yet responded to the post.