At 18-years-old, Zach Sobiech has managed to touch the lives of millions of people and leave behind a legacy for his family and friends. Sobiech was diagnosed with osteosarcoma, a rare form of bone cancer, at the age of 14. He lost his battle with the disease on Monday. 

Last year, Sobiech was told by doctors that he only had a few months to a year to live. Upon being diagnosed he took his love for music to write songs as a way to say goodbye to family and friends.

In December, he wrote, recorded and released "Clouds," a song about facing death on YouTube.

"Writing goodbye letters weren't Zach's style, so he put his heart into song lyrics. He released two albums, performed alongside some of today's best musicians and achieved a dream of helping raise money and awareness for osteosarcoma research," the Children's Cancer Research Fund wrote on their website.

His song received worldwide attention after his story appeared on CNN. The video has over three million likes and even resulted in a star-studded video montage earlier this month. Celebrities like Ashley Tisdale, Rachel Bilson, Anna Faris, Jason Mraz, Sara Bareilles, Jenna Fischer and many more told the teen how inspiring he was to each of them.

The Children's Cancer site announced Sobiech's passing on their website writing that "Zach was at home and at peace with those he loved most. Zach's life ended just as he lived, embraced by the love of his family, friends, grace and music.

"Cancer may have taken Zach too soon, but he leaves a lasting legacy that many of us will never achieve," it said. "His message of love and hope delivered through infectious lyrics and simple tunes have imprinted on the minds and hearts of millions around the world."

Sobiech's family also released a statement thanking people for listening and helping him bring his message and his music to the world.

Sobiech's story was so inspiring that a media company, SoulPancake, wanted to make a documentary about his life for their series "My Last Days."

He was also named by People Magazine as one of the Heroes Among Us earlier this year.

"We're approaching that year mark," he told People. "It's scary to think about, but the key is to not feel bad for yourself."