I don't believe "OPRAH" is a single person; I think it's a brand. If you check the images going back in time, you'll see the role was not always "played" by the same person
"lifetime actor"
I believe it was simple replacement; Cloning?
Wouldn't she look the same over the years to a greater degree if it was cloning.
Much simpler just to replace.
Check it yourself. // Vid related