Peter Davison (in-universe)

Peter Davison was an actor that the Doctor once saved from a Krynoid. He thought that something seemed familiar about him.

The Eleventh Doctor once fell into a parallel universe where he found that his life existed as a TV show called Doctor Who. He was surprised to learn there that Peter Davison existed in that universe as well, and played his fifth incarnation on TV. (COMIC: The Girl Who Loved Doctor Who)

Behind the scenes
All Creatures Great and Small exists in the DWU. In the real world, Peter Davison played one of the main characters in it.

Information from invalid sources
In the 1999 television story The Kidnappers, Peter Davison played a version of himself who was kidnapped by two obsessed fanboys (David Walliams and Mark Gatiss), who act inappropiately towards Davison.

In NOTVALID: The Five(ish) Doctors Reboot, Peter Davison portrays himself again.