Musnad Ahmad 1166:15

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Yazid ibn Abi Ziyad, who said: I asked ‘Abdullah ibn al-Harith about the Duha (forenoon) prayer. He said: I reached the companions of the Prophet, may Allah bless him and grant him peace, while they were numerous, and not one of them told me that he saw the Messenger of Allah, may Allah bless him and grant him peace, praying the Duha prayer, except Umm Hani’. For she said: "The Messenger of Allah, may Allah bless him and grant him peace, entered upon me on the day of the Conquest, on a Friday. He performed ghusl (ritual bathing), then he prayed eight rak‘ahs."