In the final scene of The Day of The Doctor, there is a lineup of all 12 of the Doctors so far:
Clearly this shot features a lot of fakery and CGI, as three people on there are dead, five haven’t aged well, and one is a notorious curmudgeon. Only the three at the front are real: Hurt, Smith and Tennant.
Now apart from the effect looking absolutely awful (Paul McGann seems to have no neck, and Christopher Eccleston appears to have had his stretched), one of the fake shemps doesn’t even seem to have a real actor’s head.
To my knackered eyes, it looks like the fake Tom Baker is actually a fake fake Tom Baker, and is really the head from the Waxworks Dummy used in the Five Doctors publicity photos:
It is the sort of thing that Moffat would do.