RIP Avalanna is trending on Twitter as Justin Bieber mourns the loss of a young avid fan, Avalanna Routh. The 6-year-old girl, who fondly called herself Mrs Bieber, succumbed to brain cancer Wednesday.

"Our darling Avalanna went to Heaven this morning," posted her family on Twitter.

Bieber met Avalanna after her family started a social network campaign using #MrsBieber. The campaign called "Get Avalanna to Meet Justin Bieber" gathered a lot of support that Mrs Bieber ultimately had a very special date with the pop idol.

Bieber flew Avalanna and her mother to New York for an early Valentine's Day date. He played board games with the adorable little girl. He tweeted it was "one of the best things I have ever done."

Avalanna was diagnosed with cancer when she was only 18 months old.

Bieber fans are also grieving the loss of the brave young girl. Many of them had supported Avanna in her family's campaign for a date with their idol, Justin Bieber.

Here are some of the tweets posted in memory of Avalanna aka Mrs Bieber:

‏@JustLoveJus10: My heart literally dropped when i saw Justin tweet "RIP Avalanna" I am going to cry.

@jusitnbjeber: You still alive in my heart. I will never forget you my princess. RIP Avalanna

@kidrauhlcookie: Today the world lost one of it's most precious and strong fighters. RIP Avalanna. Now you're a beautiful angel above, guiding us all.

‏@psandhu94: Just yesterday it felt like "Pray For Avalanna" was trending and today "RIP Avalanna" is trending....we miss you so much Ava:'(

@sydney_janelle7: Night guys. Today has been absolutely terrible, I pray for Avalanna's family and friends. RIP Avalanna, you will be missed. <3

@BelieberSwagguh: Avalanna called Scooter her "brother in law." I miss our adorable little angel. This family won't be the same without her, RIP Avalanna.

Click 'Start' to see some of Avalanna's best photos with Justin Bieber.

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