Sunan an-Nasa'i, Book 1, Hadith 227 (In-Book) ⓘ

It was narrated from Umm Hani' that she went to the Prophet on the day of the Conquest (of Makkah) and found him performing Ghusl while Fatimah was concealing him with a garment. She gave him Salams and he said: "Who is this?" She said: "Umm Hani'." When he had finished his Ghusl he stood up and prayed eight Rak'ahs wrapped in a garment.

أَخْبَرَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ، عَنْ عَبْدِ الرَّحْمَنِ، عَنْ مَالِكٍ، عَنْ سَالِمٍ، عَنْ أَبِي مُرَّةَ، مَوْلَى عَقِيلِ بْنِ أَبِي طَالِبٍ عَنْ أُمِّ هَانِئٍ، رضى الله عنها أَنَّهَا ذَهَبَتْ إِلَى النَّبِيِّ صلى الله عليه وسلم يَوْمَ الْفَتْحِ فَوَجَدَتْهُ يَغْتَسِلُ وَفَاطِمَةُ تَسْتُرُهُ بِثَوْبٍ فَسَلَّمَتْ فَقَالَ ‏ "‏ مَنْ هَذَا ‏" ‏ ‏.‏ قُلْتُ أُمُّ هَانِئٍ ‏.‏ فَلَمَّا فَرَغَ مِنْ غُسْلِهِ قَامَ فَصَلَّى ثَمَانِيَ رَكَعَاتٍ فِي ثَوْبٍ مُلْتَحِفًا بِهِ ‏.‏