Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) narrates that Sayyiduna al-Fadl bin Abbas (may Allah be pleased with him) was riding behind the Messenger of Allah (peace and blessings be upon him) when a woman from the tribe of Khath'am came to ask him a ruling. Al-Fadl began looking at her and she began looking at him, so the Messenger of Allah (peace and blessings be upon him) began turning al-Fadl's face to the other side. She said: O Messenger of Allah! The obligation of Hajj that Allah has placed upon His servants has come upon my father while he is old; he cannot stay steady on the saddle. Shall I perform Hajj on his behalf? He (peace and blessings be upon him) said: "Yes." This took place during the Farewell Hajj.
Hadith Referenceالمعجم الكبير للطبراني / باب الفاء / 15813