Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said: I said: "O Messenger of Allah! Has Surah al-Hajj been given distinction with two prostrations?" He (peace and blessings be upon him) said: "Yes. So whoever does not prostrate at them, let him not recite them (in his recitation)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14917