Devastated Justin Bieber mourns young fan
The Canadian singer took to Twitter after he was told that six-year-old Avalanna Routh had passed away on Wednesday morning after a battle with cancer.
He wrote: "Just got the worst news ever. one of the greatest spirits i have ever known is gone. please pray for her family and for her."
He added: "RIP Avalanna. i love you."
Justin then posted a link to a 'Cure AT/RT Now' web page, which encourages donations for the treatment of atypical teratoid rhabdoid tumors - the cause behind Avalanna's death.
He added: "Please show respect to her and her family. say a prayer for her and for them. i miss her."
Justin then touchingly uploaded a photo of him with little Avalanna, along with the caption: "My angel".
The 18-year-old first met Avalanna - or "Mrs. Bieber", as she liked to be called - on Valentine's Day.
He flew to New York for a special date with her and her mum following an online campaign called "Get Avalanna to Meet Justin Bieber".
He wrote after their meeting: "That was one of the best things i have ever done. she was AWESOME! feeling really inspired now #MrsBieber."
Justin saw Avalanna several more times before she died.
Following her passing, Justin vows to "make the most of every day".