Muhammad bin Ibrahim narrated from Sayyiduna Qays bin Amr (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) saw a man praying two rak'ahs after the Subh (Fajr) prayer, and he (peace and blessings be upon him) said: "Is the Subh prayer prayed twice?" The man said: I had not prayed (the Sunnah of Fajr) before it, so I have prayed them now. At this, the Prophet (peace and blessings be upon him) remained silent.
Hadith Referenceالمعجم الكبير للطبراني / باب القاف / 16027