It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that he proclaimed the Talbiyah for Hajj and Umrah, then performed a single Tawaf for both of them, and said: I saw the Messenger of Allah (peace and blessings be upon him) doing the same.
Hadith Referenceصحيح ابن خزيمه / جماع أبواب ذكر أفعال اختلف الناس فى إباحته للمحرم، نصت سنة النبى صلى الله عليه وسلم أو دلت على إباحتها / 2746