It was no great secret of the animosity felt between Bette Davis and Joan Crawford, but by 1962 both of their careers and their age respectively compelled both to take the great roles in "Whatever Happened To Baby Jane?".
By all accounts, the set for the filming was cordial and polite, likely due to the skills of Director Robert Aldrich.
The two great actresses play sisters living in the same home. Child stars in vaudeville, their lives are forever altered when Crawford is crippled and blame is put on Davis' being drunk behind the wheel.
The plot and the relationship is frankly irrelevant. This is a movie with larger than life women providing tour de force performances. Bette Davis would get few more good roles, including "Hush Hush Sweet Charlotte", but Crawford would get roles that were lesser in stature, after quitting the aforementioned Davis vehicle.