Hollywood used to be a different place, populated by different people. Jimmy Stewart, already a star, enlisted before Pearl Harbor, became a pilot, then an instructor, and made numerous training films. Not content with that, he landed a job with a B-24 Squardon headed for Europe. He rose to squardon commander and flew his 20 combat missions, including the Bloody Thursday raid on Schweinfurt. He could have rotated home and spent the rest of the War selling War Bonds and being wined and dined across America, but he stayed behind when the survivors of his squardon went home, and spent the rest of the European War as a staff officer, rising to full Colonel.
Actually his career went further, he joined the Air Force Reserves, and retired as a Brigadier General. He even flew in Viet Nam.