Captain Megan Russert of the Baltimore Police Department in 'Homicide: Life On The Street' is related to NBC newsman Tim Russert.
Vera Louise Gorman is related to the late Art Carney, as seen on 'Alice'.
And Luke Skywalker believes that he is kin to Mark Hamill; or so it was mentioned on 'The Muppet Show'.A new real to reel relative showed up on 'Entourage' this week. "Mrs. Ari" (we don't know the first name of Ari Gold's wife) had family over to break fast at the end of Yom Kippur, and one of them was her Uncle Shelley.
Uncle Shelley was played by Shelley Berman. As nothing contradicted otherwise, I see no reason why we can't assume he was appearing as himself.