Stephen Fry (in-universe)

Stephen Fry was a celebrity who visited the Tomorrow Windows in the Tate Modern and at one point had married River Song.

Biography
In 2004, Stephen Fry was one of the celebrities that attended the unveiling of the Tomorrow Windows at the Tate Modern, as observed by the Eighth Doctor's companion Trix MacMillan. (PROSE: The Tomorrow Windows)

After the Twelfth Doctor acted incredulous that River Song — his wife — had married King Hydroflax, they both cited each other's former spouses, with the Doctor identifying Stephen Fry as one of River's. (TV: The Husbands of River Song)