Abd al-Malik bin Umayr (may Allah have mercy on him) says: I saw Mughirah bin Shu'bah (may Allah be pleased with him); he led two rak'ahs on Eid al-Fitr or Eid al-Adha, then delivered the sermon mounted on his camel, but no adhan or iqamah was given.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة العيدين / 6210