Musnad Ahmad 1275:3

Aswad ibn Amir narrated to us, Isra’il narrated to us, from Mansur, from Mujahid, from a freed slave of the family of al-Zubayr, who said: The daughter of Zam’ah said: I came to the Messenger of Allah, peace and blessings of Allah be upon him, and said: "My father, Zam’ah, died and left behind a mother of his child (umm walad), and we used to think she belonged to a certain man. She gave birth, and her child came out resembling the man we thought she belonged to." He said: So the Messenger of Allah, peace and blessings of Allah be upon him, said to her: "As for you, observe hijab from him, for he is not your brother, but he has the inheritance."