According to The Courier Mail, Stella was enjoying a relaxing day at Byron Bay's famous beach, The Pass, with the 46-year-old actor, along with her mother, Luciana Barroso, and sisters Isabella, Alexia and Gia. They were also joined by Chris Hemsworth and his wife, Elsa Pataky, and their three children. The outlet reports Stella let out a scream and ran out of the water.
After Matt and Luciana comforted Stella following the scary incident, Matt rushed to a local café to grab ice to help ease the pain, The Courier Mail reports, as paramedics treated her at the scene.
Get better soon, Stella!
Back in August 2015, the father of four had nothing but amazing things to say about his kids while chatting with ET at the opening of trainer Jason Walsh's Rise Nation fitness studio in West Hollywood, California.
"I think everything changes in little wonderful ways," he gushed. "My whole life opened up when I became a dad. I'm very much on the receiving end of all the good stuff."
PHOTOS: Matt Damon through the years
Matt Damon through the years
Matt Damon through the years
Brendan Fraiser, Matt Damon, Randel Batinkoff and Guest at the Academy Theater in Beverly Hills, California (Photo by Ron Galella/WireImage)
Matt Damon (Photo by Ron Galella/WireImage)
Matt Damon (Photo by Jim Smeal/WireImage)
Matt Damon at the Radio City Music Hall in New York City, New York (Photo by Kevin Mazur/WireImage)
THE TONIGHT SHOW WITH JAY LENO -- Episode 1274 -- Pictured: (l-r) Actor Matt Damon during an interview with host Jay Leno on December 1, 1997 -- (Photo by: Margaret Norton/NBC/NBCU Photo Bank via Getty Images)
Matt Damon during 55th Annual Golden Globe Awards at Beverly Hilton Hotel in Beverly Hills, California, United States. (Photo by SGranitz/WireImage)
BOSTON, : Oscar winning actor Matt Damon from Cambridge, Massachusetts, signs autographs prior to the Home-Run Derby during the 70th Baseball All-Star Week12 July, 1999, at Fenway Park in Boston, Massachusetts. The All-Star will be played 13 July between the American and National Leagues. (ELECTRONIC IMAGE) AFP PHOTO/Stephen JAFFE (Photo credit should read STEPHEN JAFFE/AFP/Getty Images)
368219 04: Actor Matt Damon stars as Rannulph Junuh in Robert Redford's The Legend of Bagger Vance, to be distributed domestically by DreamWorks. (Photo by David James/Newsmakers)
385569 20: (NO WHO WEEKLY) FILE PHOTO: Actor Matt Damon attends the world premiere of his new film 'All The Pretty Horses' December 10, 2000 at the Beekman Theater in New York City. A Rhodesian Ridgeback dog who resembles actor Matt Damon 'especially in the eyes' says his owner, participated in an audition for pets that look like celebrities February 15, 2001 at Universal Studios in Burbank, CA. The dog was one of several dozens pets competing for a video spot on 'Animal Planet Live', a new attraction at Universal Studios. (Photo by Robin Platzer/Liaison)
PRAGUE, CZECH REPUBLIC - JANUARY 12: (Publicist approval required for ALL usages) Actor Matt Damon on the set during filming of 'The Bourne Identity' on January 12, 2001 in Prague, Czech Republic. (Photo by Daniel Smith/Getty Images)
LONDON, ENGLAND - SEPTEMBER 24: Matt Damon attends the European premiere of 'The Martian' at Odeon Leicester Square on September 24, 2015 in London, England. (Photo by Karwai Tang/WireImage)