Harry Langdon: Soldier Man (1926)

Directed by Harry Edwards.
After the armistice, one U.S. soldier remains unaccounted for: he's wandering the fields of Bomania, hungry, thinking the war is still on. (He was in a German prison camp, escaping while his captors celebrated the Great War's end.) Turns out, he's the spitting image of Bomania's King Strudel. The prime minister wants Strudel to sign a peace treaty ending civil war with a cousin. Bomania's General Von Snootzer wants the war to continue, so he contrives to derail the treaty. Strudel is a drunk, his queen hates him. Into the mix stumbles our dough boy. If he can pass for the king, maybe the treaty can continue. But what of the queen and her plans?