Urwah (may Allah have mercy on him) said: The Prophet (peace and blessings be upon him) performed Hajj, and Sayyidah Aishah (may Allah be pleased with her) informed me that the first thing the Prophet (peace and blessings be upon him) did on arriving in Makkah was to perform ablution and then perform tawaf of the House.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9300