Well, it does not matter how famous you have been in a previous life. As a matter, we may have progress less from life being famous than a one being a simple man. Spirituality is not linked to celebrities. Fame is a manifestation of the EGO, and it does not have anything to do with our progress at a spiritual level.
Yes, we may have been famous persons in the past, but as I said, that does not mean much. For instance, if I have been the King of France, I would have been created more bad Karma that I have to repay in ten lives after.
In conclusion, a previous life could seem as unrealistic as your mind and EGO make it that way. In previous lives, we should not look who we were, but what have we learned and how much of a good Karma we have been created.
The only time when a previous life was not yours is if you are a new Soul to Earth and you receive an imprint to be able to take in the shock of a 3d plane.
For more info, you may want to read Dolores Cannon’s books. It will give you a great perspective on why we have many lives and how we can reach the next level.
https://www.amazon.com/s?k=Cannon%2Bdolores&ref=nb_sb_noss_2