Nafi' said: Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) felt cold while he was in ihram, so I put a burnus (hooded cloak) over him. He said: "What is this?" I said: "It is a burnus." He said: "Take it away from me. Do you not know that the Prophet (peace and blessings be upon him) forbade the person in ihram from wearing the burnus?"
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9074