Berlin wrote White Christmas for the film Holiday Inn, where Bing Crosby introduced it in 1942; Crosby had already sung it on radio on Christmas Day 1941, weeks after Pearl Harbor. The song states almost nothing — snow, treetops, sleigh bells, a card — and was taken up by troops overseas as a message about home rather than about the holiday. It won the Academy Award for Best Original Song, and Crosby's recording became the best-selling single ever released. Berlin, who played in only one key, worked it out on a transposing piano, as he did everything else.