Updated

Hundreds came together in St. Louis to perform in a flash mob for a teenager with leukemia the night before he underwent a bone marrow transplant, Fox2Now.com reported.

Seth Lange, 16, has been battling his illness for two years.

The mob sang, chanted and prayed for Lange outside of the hospital, as he looked on from his window.

“The goal is to get him to smile and remind him that he is not alone,” organizer Shawn Kohrs told Fox2Now.com. “I just love that kid.”

According to the report, Kohrs promoted the flash mob idea on Facebook.

“I wanted to do something big, but he is in isolation before the transplant,” he said. “No one can see him, so I thought I’d do a flash mob.”

Lange’s mother said all the support was “amazing," Fox2Now.com reported.

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