Just days after his death, a teenager's goodbye message to his friends and family, a song he wrote named "Clouds", is the number one selling song on iTunes.

Zach Sobiech, 18, passed away early Monday morning after a four year battle with cancer. But before he died, Zach was able to do something that many aren't able to do. He was able to say goodbye to his friends and family in the best way he knew how, with music. With the help of the folks at SoulPancake, Zach was able to produce and record his song "Clouds". The song was made available for purchase on iTunes, with a portion of the proceeds going to a children's cancer charity.

iTunes

After the video for "Clouds" went viral, SoulPancake was able to get dozens of celebrities to record themselves lip-synching to the song to send to Zach as a message of inspiration.

Check out "Clouds" in the video below.