Was it the 1961 Hayley Mills classic film The Parent Trap? I think it was. The film concerned two twin sisters separated at around one year of age who later meet at camp?

...according to her book, "Call Me Anna," Ms. Duke states that ABC wanted to create a show around her, but nobody really had a concept of what the show would be.
Her managers sent her to spend some time with Sidney Sheldon, (who was brought in to do the pilot,) and his family, in the hopes that it would help him to form some idea for a show.
Ms. Duke says that although he jokingly relates it, she believes that he came up with the idea for her to play a dual role based on her behavior; she had a perky side, and a "corporate executive" side. Perhaps, "The Parent Trap" exerted some influence as well, but apparently Patty's own behavior sparked Mr. Sheldon's creative interest.

I remember seeing the show in the early 1970's, In fact I called my dad Poppo as Patty called her tv father. I read all the enquirer type magazines of the day reading about her romance with
desi arnaz.

I wish they would bring back this show.........