It is narrated from Sayyiduna Ibn Amr, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said twelve takbirs in the Eid prayer: seven in the first rak'ah and five in the second, and he did not perform any nafl prayer before or after it. Imam Ahmad, may Allah have mercy on him, also holds this opinion.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 6688