According to her Wikipedia article, she was raised by her paternal grandmother and stepmother after her mother, Elisabeth Christine Ulrike of Brunswick-Wolfenbüttel, was made pregnant out of wedlock. Her father, Friedrich Wilhelm II, divorced her mother and imprisoned her mother for the rest of her long life with no contact with Frederica Charlotte. Frederica Charlotte made a favorable impression in Great Britain.

Princess Frederica Charlotte of Prussia by Joseph Friedrich August Darbes (location unknown to gogm)
