Musannaf Ibn Abi Shayba 27:568

Ali ibn Mushir narrated to us, from al-Ajalh, from al-Sha'bi, who said: The Messenger of Allah (may Allah bless him and grant him peace) was approached when he conquered Khaybar, and it was said to him: "Ja'far has arrived from the Negus." He said: "I do not know which of the two I am more joyful about: the arrival of Ja'far or the conquest of Khaybar." Then he met him, embraced him, and kissed him between his eyes.