It was narrated from 'Imran bin Husain that:
The Prophet (ﷺ) prayed three (rak'ahs) then said the taslim. Al-Khirbaq said: "You prayed three." So he led them in praying the remaining rak'ah, then he said the taslim, then he did the two prostrations of forgetfulness, then he said the taslim (again).