Mujahid (may Allah have mercy on him) narrates from Sa'id, from Sayyidah Umm Hani bint Abi Talib (may Allah be pleased with her), that she said: On the day of the Conquest of Makkah, the Messenger of Allah (peace and blessings be upon him) came to me while he (peace and blessings be upon him) was covered in dust. He (peace and blessings be upon him) called for a vessel, and it is as if I can see the trace of dough in it. I poured water into it, then he (peace and blessings be upon him) ordered that a cloth be put up as a screen between me and him, and the screen was put up. Then he (peace and blessings be upon him) stood and poured water over himself, then stood and prayed eight rak'ahs of the Duha (forenoon) prayer. Mujahid said: I narrated this hadith to Ibn Abbas (may Allah be pleased with them both), and he said: "This is the Ishraq prayer."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21438