Neither Bing Crosby nor Fred Astaire were too crazy about the early drafts of White Christmas. In particular, they were paranoid about how their characters would be portrayed—but for opposite reasons.
Astaire didn’t want his character to come across as too old. He preferred the spry, reckless playboy character that he’d been cultivating in films for the past 25 years, not the script’s grizzled show biz veteran who was old enough to have served in World War I and to have appeared in minstrel shows in vaudeville (even though—then in his mid-50s—that’s exactly what he was).
Crosby, however, didn’t want his character to come across as too young. He’d been pursuing a long-term image of wise, calm, reasonable, sage. The first scripts did have Fred as the playboy and partner Bing as his watchdog. Still, Crosby felt all the skirt chasing made him appear “too frivolous” and “young” in nature.
So, privately, Crosby was relieved when Astaire stepped out and Donald O’Connor was signed. The casting of O’Connor allowed the relationship to change from that of two buddies on the prowl to that of a mature older GI and an adoring younger GI, a dynamic preserved when Danny Kaye joined the cast.