Sixteen-year-old Olivia Wise, whose cover of Katy Perry's "Roar" soared to more than a million YouTube views since October, died Monday of inoperable brain cancer.
Perry heard about Wise's passing and took to Twitter to remember her:
Olivia Wise, I can hear you singing with the angels now. Your spirit & strength has inspired me & so many others... May you rest in peace.
— Katy Perry (@katyperry) November 26, 2013
Wise's viral video (watch, above) shows her in a wheelchair singing the song's encouraging lyrics in Toronto. It was her first time in a recording studio.
"She couldn't walk or stand, she didn't have her full breath or the energy she used to, and she was managing her new pains and new limitations," the video's YouTube description says. "While her physical condition was rapidly fading, her spirit remained untouched."
That recording from September caught Perry's attention, and the pop star recorded this message to Wise in October:

Wise's rendition of "Roar" is available to The Liv Wise Fund, which was set up to raise money for brain cancer research. The fund has raised $108,146 of its $150,000 fundraising goal.
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Image: YouTube