(People) - This could easily be the most moving celebrity shout-out of all time.
Zach Sobiech, 17, of Lakeland, MN inspired millions with his cancer fight and the farewell song he penned, "Clouds."
Now, a slew of celebrities are showing their support for the brave teenager (he's been diagnosed with osteosarcoma) with a tribute video set to his song, in an effort to raise awareness and funds to help find a cure for childhood cancer.
Among the stars featured in the new video, which airs on Rainn Wilson's SoulPancake YouTube channel: Ashley Tisdale, Colbie Caillat, Anna Faris, Jason Mraz, Sara Bareilles, Jenna Fischer, The Lumineers, Rachel Bilson, Ed Helms, Phillip Phillips and more.
Watch the video here: