Justin Bieber Fan Avalanna Routh Dies At 6

One of Justin Bieber's youngest and most ardent fans, 6-year-old Avalanna "Mrs. Bieber" Routh, died on Wednesday of brain cancer. "Just got the worst news ever," Bieber tweeted after Routh's death. "One of the greatest spirits I have ever known is gone. Please pray for her family and for her," Bieber said. "I miss her." Bieber later posted a picture of "my angel" (below), and added "RIP Avalanna. I love you."

Bieber first learned of Routh thanks to a "Get Avalanna To Meet Justin Bieber" campaign on Facebook and the Twitter hash tag #MrsBieber. Routh, who was so infatuated with Bieber that her nurses orchestrated a faux wedding at the hospital for her to marry a cardboard cutout of her idol, was diagnosed with AT/RT (atypical teratoid rhabdoid tumor), a cancer of the brain and spinal cord, when she was 18 months old. After discovering her story, Bieber flew his cancer-stricken devotee and her mother out to New York for an early Valentine's Day date, making Routh's dreams come true.

Routh's family, from Merrimac, Mass., announced her passing to the world on Twitter. “Our darling Avalanna went to Heaven this morning,” her family wrote. “Oh Avalanna, the brightest star — you took our hearts with you, our greatest love.”

Get Uinterview's FREE iPhone App For Daily News Updates here.

Read others:

Moon River,' 'Butterfly' Crooner Andy Williams Dies At 84

WATCH: Justin Bieber, The Wanted Perform On 'The Voice'

Pioneering Comedian Phyllis Diller Dies At 95, Stars React On Twitter