David Tennant (in-universe)

David Tennant was an actor who portrayed "Doctor Who" in a television programme of the same name, and was considered by the Twelfth Doctor to be one of the greatest actors on Earth. He was brought together, along with many other actors to portray "Doctor Who", for a special breakfast in "London's glittering West End". The Twelfth Doctor considered making an appearance, to "see what these fictions [were] like." (WC: Peter Capaldi and Simon the Shy Cyberman Invite You to Breakfast with 7 Doctors)

Behind the scenes
Evidently, "David Tennant" here was intended to be an in-universe version of the real David Tennant, who portrayed the Tenth Doctor. Although he was not given a clear in-universe illustration during the narrative of WC: Peter Capaldi and Simon the Shy Cyberman Invite You to Breakfast with 7 Doctors, the end of the webcast included a screen featuring photographs of each Doctor who would be present at the event, in-costume as "the Doctor". If taken as an in-universe representation of Tennant, this qualifies as the only in-universe illustration of the character outside of parodies.