Diahnne Abbott played in Taxi Driver with Robert De Niro... You
can say that De Niro was "THE" Star of that movie of 1976 along
with Cybill Shepherd and Jodie Foster but it's not the case of
Abbott who had almost no part at all...
They got married that year.
They also played together (Now husband and wife) in "New York,
New York" in 1977 but again the co-stars were Liza Minelli & De
Niro... Abbott was merely a n "extra" with line...
You can say that in 1982 "The King of Comedy" Abbott and De Niro
have been the co-star of this movie.
Finally and just for more information Diahnne Abbott Played with
another De Niro (Drena this time, her daughter) in the 2002 movie
Soliloquy.