Louis Zamperini, an Olympic runner and a World War II hero, has died at age 97. Zamperini’s astonishing story of survival is the subject of the upcoming Universal film Unbroken, directed by Angelina Jolie.

Zamperini’s death was confirmed in a statement from Universal to The Hollywood Reporter and other news outlets.

“Having overcome insurmountable odds at every turn in his life, Olympic runner and World War II hero Louis Zamperini has never broken down from a challenge,” his family said in the statement. They confirmed that he recently battled pneumonia and died after a 40-day battle with the illness.

“His indomitable courage and fighting spirit were never more apparent than in these last days,” the statement continues.

Jolie was also quoted as saying, “It is a loss impossible to describe. We are all so grateful for how enriched our lives are for having known him. We will miss him terribly.”

As for the studio itself, they said that they look forward to the December release of the film with “a renewed sense of responsibility in bringing Louie's abundant life and indomitable spirit to the screen.”

Zamperini, who was named the 2015 Rose Parade Grand Marshall in May, lead an astonishing life even before the war. He made the 1936 U.S. Olympic Team and was the youngest American to qualify for the 5,000 meters event. Then, in 1941, he joined the U.S. Army Air Force and served in the Pacific.

In 1943, his plane crashed in the ocean and he and two survivors drifted for nearly 50 days. They washed up on a Japanese island and were held captive. He was assumed dead until he came home after the war. In 1946, he married Cynthia Applewhite and they remained together until she died in 2001.

Laura Hillenbrand turned his story into the best-selling book Unbroken. The film version opens on Dec. 25.