I saw the Messenger of Allah ﷺ mount his riding camel at Dhu al-Hulayfah, then begin the talbiyah the moment it stood upright with him on its back.
رأيت رسول الله ﷺ ركب راحلته بذي الحليفة، ثم يهل حين تستوي به قائمة.
Bukhari related it in Hajj (1514) and Muslim in Hajj (1187: 29), both through Ibn Wahb, from Yunus, from Ibn Shihab, that Salim bin Abdullah informed him, that Abdullah bin Umar (said, then he mentioned it).