In 'The Impossible Astronaut', the Doctor got himself inserted into the Laurel and Hardy movie "Flying Deuces" in order to attract the attention of his Companions Amy and Rory.
This must have been a special print of the film, because he doesn't show up in actual copies of the movie; and the director and editor of "Flying Deuces" would never have allowed that footage into the final print as it ruins the storyline and detracts from the two main stars.
I'm guessing that the Doctor sought the help of Billy Shipton sometime after Billy's arrival in 1969, once he had established himself as a video/DVD publisher. So not only did he insert those Easter Eggs into the disks meant for Sally Sparrow, he also put together this rarest of Laurel and Hardy movies.
Over at LaurelandHardy.org, they quickly took notice of the intrusion of the Doctor into the world of the Sons of the Desert and they also offered up a picture of what might have happened when Stan and Ollie did meet the Doctor.....