It is narrated from Sayyiduna Abu Ayyub al-Ansari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) always used to pray four rak'ahs before Zuhr when the sun passed the meridian. (Then the narrator) narrated a similar hadith.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4018