A teenager who endured a 20-hour brain surgery to remove a tumour had her one wish of meeting Panic! at the Disco come true.

Alyssa Rose from Nova Scotia, who went under the knife in October to remove a tumour from her brain stem, wrote a letter to the band in December.

It ended up going viral thanks to her dad Shawn Rose, who had bought tickets for the band’s concert near Montreal. He posted the letter on Twitter where it was shared more than 100,000 times.

The tweet caught the attention of band management who reached out to the family and offered them backstage passes.

On Saturday, Alyssa and her family made the 14-hour drive through a blizzard to meet the band’s front man Brendon Urie backstage.

“I had people from Europe message me, people from South Africa, Phillipines, Hong Kong,” Rose told CTV Atlantic.

“For what she went through with her 20-hour brain surgery, I'd do anything for that little girl.”

Alyssa admitted she was ‘fan-girling hard’ when she penned the note to the singer .

“It was so cool, I'm so happy. He gave me a big hug and everything,” she said, showing off a signed t-shirt.

Alyssa’s mother Lynn Rose, who also underwent surgery to remove a tumour on her brain stem 16 years ago, said her daughter will never forget the meeting.

Her father was also thrilled with the meeting.

"I'm still in shock,” he told CTV Atlantic. “Especially for someone to go out of their way to reach out and fulfill Alyssa's wish. It means a lot."

Alyssa credits the band’s music with helping to get her through her diagnosis and recovery.

“I find music has a way, it just kind of makes me happy, brightens up my day,” she said.