It is narrated from Hazrat Ibn Buhaina (may Allah be pleased with him) that once the Noble Prophet (peace and blessings be upon him) saw a man performing the two Sunnah rak'ahs of Fajr at a time when the congregational prayer had already begun. After the prayer was finished, the people surrounded him, and the Noble Prophet (peace and blessings be upon him) said, "Are there four rak'ahs in Fajr?"