I’ll do better and give you two.
Peter Sellers and David Niven.
In September 1943 Peter Sellers joined the RAF. He wanted to be a pilot, but his poor eyesight made it impossible for him so he got ground duty. He found it boring so he applied and was accepted into a entertainment troupe. He toured the UK and then India, Ceylon and Burma. After the war he served in Germany and France.
David Niven had already had a military career before becoming an actor, but when the war broke out he rejoined. He was recommissioned as a lieutenant in 1940 and was assigned to a motor training battalion. He thought it was boring so he joined the commandos.
He commanded the “A” Squadron GHQ Liaison Regiment (aka “Phantom”), special reconnaissance. He was promoted to captain in 1941. During the war he aided in Operation Copperhead, and saw action on D-Day and during Operation Market Garden. There is a story that during the Battle of the Bulge he was stopped by US troops and they tried to stop German saboteurs by asking trivia questions. He was asked who won the 1943 World Series and he replied with “Haven’t the foggiest idea, but I did co-star with Ginger Rogers in ‘Bachelor Mother’!” He also was awarded a US Legion of Merit.