This is so sad!
Zach Sobiech was just a normal 14-year-old teenager living in Minnesota when his doctors diagnosed him with osteosarcoma - a rare form of bone cancer.
After a long fight with the cancer, doctors told Zach he only had a few months to live. Zach turned to music and recorded a song called Clouds, a song about dealing with death, which has since gone viral and has been viewed by over three million fans!
So it is with a heavy heart that we bear the sad news that Zach passed away on Monday morning. He was 18 years old.
Here's what the Children's Cancer Research Fund said in a statement: