Musannaf Ibn Abi Shayba 3:810

Muhammad ibn Bishr narrated to us, he said: ‘Amr ibn Kathir narrated to us, he said: Ibn Kaysan narrated to me, from his father, who said: I saw the Prophet, may Allah bless him and grant him peace, pray Dhuhr and ‘Asr in a single garment, wrapping himself in it.