When the world just seems full of bad news across the board, it's nice to come across a heart warmer. A little girl struggling with a rare cancer has had her dreams come true for Valentine's Day after meeting her pop idol Justin Bieber - and 'marrying' him. Avalanna Routh, six, has fought an aggressive and deadly brain cancer ATRT since she was a baby, undergoing chemotherapy and radiation treatments. Her wish was to meet Bieber in person - who found out about her request after her family appealed to him via Facebook. It lead to the pop superstar flying the little girl and her family from Boston to New York for a special Valentine's visit yesterday. Avalanna's mother Aileen told the Today show: 'It was wonderful, just another fun moment.' After the special day out, Avalanna was completely smitten with her hero, saying: 'I love Bieber...baby, baby' and singing from one of the superstar's hit songs. Avalanna's dream was realised thanks to help from the Jimmy Fund, a charity that has helped children fight cancer for more than 60 years. Mrs Routh told 7News: 'She's beaten all the odds. It's a very aggressive, rare disease, and she's been in treatment for five and a half years.' ATRT, or atypical teratoid rhabdoid tumor, is so rare that less than 30 new cases of the cancer are diagnosed in the U.S. each year. There is no known cure. For more information and to donate to research, visit cureatrt.org.