Not as a regular thing. However, various stories have featured more than one Doctor. "The Three Doctors" featured the First, Second and Third Doctors. "The Five Doctors" featured the First, Second, Third, and Fifth Doctors (and un-used footage of 4th Doctor, but he was never on set for that episode). "The Two Doctors" featured the Second and Sixth Doctors. "The Day of the Doctor" featured the War Doctor and the Tenth and Eleventh Doctors. Meanwhile the 'minisodes' have also featured more than one Doctor. "Dimensions in Time" featured the Third, Fourth, Fifth, Sixth and Seventh Doctors. And "Time Crash" featured the Fifth and Tenth Doctors.