The Bishop's Wife (1947)
The Bishop's Wife stars David Niven, Lorretta Young, and Cary Grant. It centers around the story of the angel, Dudley. Dudley is sent to earth to help Niven's character deal with building a new cathedral and the stresses involved as well as his wife (Young) and the toll Henry's work has taken on their marriage.
This is a great movie. It's simple and never leaves the Christmas background. David Niven's rousing sermon at the end can even rival those of well known clergymen today. It's underlying tones of human frailty and the tendency of human beings to focus on the less important things in life while ignoring the most important ones is brought out in Dudley's relationship with Julia (Young).
The movie was released by RKO in 1947. Niven was originally cast as the angel, Dana Andrews as the bishop, and Teresa Wright as his wife. However, Wright had to bow out due to pregnancy. According to Robert Osborne, Andrews was lent to RKO in order to obtain Loretta Young. Koster then brought in Cary Grant, but he wanted to play the angel, so the role of the bishop was given to Niven.
from Wikipedia™