Ibrahim bin Suwayd (may Allah have mercy on him) said: Alqamah (may Allah have mercy on him) led us in the Zuhr prayer with five rak'ahs. When he finished with the salam, the people said to him: You prayed five rak'ahs. He said: I did not do that. Then he said: Is that so, O A'war? I said: Yes. So he turned and performed the two prostrations of forgetfulness, then said the salam. Then he narrated from Abdullah (bin Mas'ud) (may Allah be pleased with him), from the Prophet (peace and blessings be upon him), that he (peace and blessings be upon him) prayed five rak'ahs. The Companions began whispering among themselves, so he (peace and blessings be upon him) said: "What is the matter with you?" They said: Has something been added to the prayer? He (peace and blessings be upon him) said: "What is that?" They said: You prayed five rak'ahs. He (peace and blessings be upon him) said: "No, rather I forgot." Then he (peace and blessings be upon him) turned and performed two prostrations.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9809