According to Eddie Muller on TCM's Noir Alley (2017-10-15), Farley Granger and Cathy O'Donnell first appeared together in They Live by Night (1948), filmed at RKO Pictures in 1947 but put on the shelf by new studio boss Howard Hughes. Former RKO Production Chief Dore Schary feared the picture would never be released, so he paired the actors again in Side Street (1949) at his new studio, M-G-M. Hughes learned of this and, wanting to beat Schary to the punch, finally released "They Live by Night" in the USA in November 1949, just a few weeks before "Side Street" opened nationwide.
About 44 minutes into the movie, our hero enters a bar under the Third Avenue El, The building number is 915, and you can barely make out the writing on the front window: Clarke's Cafe. That's none other than P.J. Clarke's at 915 Third ave., still there and barely changed.