Matt Damon is currently on vacation in Australia with his family to visit his friend and fellow actor, Chris Hemsworth.
During a day at The Pass in Byron Bay, Damon's youngest daughter Stella, 6, was stung by a jellyfish.
Witnesses claim that Stella was screaming after being stung, Courier Mail reports.
Damon rushed to a nearby cafe to get ice for his daughter.
Paramedics were called to the scene to treat the daughter of The Bourne Identity star.