Musannaf Ibn Abi Shayba 3:2135

Ibn Fudayl narrated to us, from Husayn, from Ikrimah, who said: The Prophet (peace be upon him) prayed with the people three rak'ahs, then he turned away. Some of the people said to him, "Has something happened in the prayer?" He said, "And what is that?" They said, "You did not pray except three rak'ahs." He said, "Is that so, O Dhu al-Yadayn?"—and he was called Dhu al-Shimalayn—he said, "Yes." He said, "So he prayed a rak'ah and prostrated two prostrations."