It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) prayed Zuhr with five rak'ahs. It was said: O Messenger of Allah, has something been added to the prayer? He said: "What is that?" They said: You (peace and blessings be upon him) prayed five rak'ahs. So he (peace and blessings be upon him) performed two prostrations.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9803