Stan Lee honored military service members on Veterans Day with social media posts highlighting his time in the Army during World War II a day before he died at age 95.

The Lee family attorney confirmed the legendary Marvel superheroes creator’s death on Monday. He was pronounced dead at Cedars-Sinai Medical Center in Los Angeles.

A day before his death, Lee celebrated Veterans Day by posting a throwback black-and-white photo on Facebook, Instagram and Twitter of himself during his time in the U.S. Army Signal Corps. Sunday’s posts were his final ones before his death.

“Thank you to all of America’s veterans for your service. Fun fact: Stan’s official US Army title during WW2 was ‘Playwright.’ #VeteransDay,” the post on Sunday read.

Lee enlisted in the Army in 1942 shortly after the attack on Pearl Harbor and worked as a lineman before he transferred to technical writing and creating posters, the Department of Defense News reported. The military recognized his impeccable writing skills, which he later used to develop some of the most celebrated superhero characters.

Lee’s time in the army ended in 1945.

STAN LEE, LEGENDARY MARVEL SUPERHEROES CREATOR, DEAD AT 95

The Marvel Comics icon was inducted into the Signal Corps Regimental Association in March 2017 — a moment he says trumps some of his top accomplishments.

“I want to tell [fans] if you’re looking, this is one of my proudest moments. Excelsior!” Lee said when he received a certificate of his lifetime membership and coin from the battalion. “Signal Corps forever.”

Lee previously said his comic book characters were influenced by some of his life experiences.

As the top writer at Marvel Comics and later as its publisher, Lee was widely considered the architect of the contemporary comic book. He revived the industry in the 1960s by offering the costumes and action craved by younger readers while insisting on sophisticated plots, college-level dialogue, satire, science fiction, even philosophy.

Some of his most well-known characters include the Fantastic Four, the Hulk, Spider-Man, Iron Man, which all have been brought to life in films.

The Associated Press contributed to this report.