Musnad Abu Ya'la al-Mawsili 154:155

Abu Khaythama narrated to us, Muhammad ibn Khazim narrated to us, Hajjaj narrated to us, from ‘Ata’, from Ibn ‘Umar: That he used to begin the Talbiyah when his riding beast stood upright with him, and he would begin the Talbiyah after the prayer. And he used to say: "Indeed, the Messenger of Allah, may Allah bless him and grant him peace, used to do that."