Twice Blessed (1945)

Stephanie and Terry are identical twins who have been separated since their parents, Jeff and Mary, divorced seven years before. Each envies the other's lifestyle, so they decide to switch families for a day or two. They soon find that it is harder than just looking like someone to be able to do what that person is expected to do. After they realize that their charade may bring their parents back together, they agree to continue it. A major complication starts when Jeff's girlfriend and co-worker Alice finds out the real story.