Musnad Ahmad 1166:18

Waki’ narrated to us, Shu’bah narrated to us, from ‘Amr ibn Murrah, from ‘Abd al-Rahman ibn Abi Layla, who said: No one informed us that the Messenger of Allah (may Allah bless him and grant him peace) prayed the Duha (forenoon) prayer except Umm Hani’. For she said: "The Prophet (may Allah bless him and grant him peace) entered my house upon me and performed ghusl on the day of the conquest of Makkah, then he prayed eight rak'ahs, in which he made the bowing and prostration light."