Sarai, Avram’s wife, had borne him no children. She had an Egyptian maidservant whose name was Hagar.
Bereishis Rabbah (Hagar as Pharaoh’s daughter — classic tradition)
English: Hagar — Pharaoh’s daughter. When Pharaoh saw the miracles done for Sarah in his house, he gave him his daughter, saying: Better that my daughter be a servant in this house than a mistress in another house.
Supplementary classical material not listed by Torah Temimah under this exact passuk.