This could easily be the most moving celebrity shout-out of all time.
Zach Sobiech, 17, 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.
Sobiech was featured as one of PEOPLE's Heroes Among Us earlier this year. His music video for "Clouds" is up to 2.6 million views and counting.
Last May, doctors gave the teenager a grim prognosis: he had up to a year to live. "We're approaching that year mark," Zach told PEOPLE in March. "It's scary to think about, but the key is to not feel bad for yourself."
The song "was for me and my family," he said. "I needed to get that emotion out and they wanted something they could remember me by."
He's also been using his remaining time to help others, teaming with the Children's Cancer Research Fund and hopes to raise awareness for kids suffering from his rare form of cancer.
"Our goal," he said, "is to give other kids with osteosarcoma a chance."
J. Dunn Photography