Musnad Abu Ya'la al-Mawsili 209:37

Muhammad ibn Isma'il ibn Abi Samina narrated to us, Mu'tamir narrated to us, from his father, from Abu 'Uthman, who said: Umm Salamah said: The Prophet, peace and blessings of Allah be upon him, was speaking to a man. When he stood up, he said: "O Umm Salamah, who is this?" I said: "Dihyah al-Kalbi." I did not know that it was Gabriel, peace be upon him, until I heard the Messenger of Allah, peace and blessings of Allah be upon him, speaking to his companions about what had passed between us. I said to Abu 'Uthman: "Who narrated this to you?" He said: "Usamah ibn Zayd narrated it to me."