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. (COMIC: The Girl Who Loved Doctor Who)

Behind the scenes
All Creatures Great and Small and Button Moon exists in the DWU. In the real world, Peter Davison played one of the main characters in the former, and performed, alongside his former-wife Sandra Dickinson, the theme song for the latter.

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.