Beatty and Keaton's romantic relationship also began to deteriorate during filming. Peter Biskind wrote about the making of "Reds", "Beatty's relationship with Keaton barely survived the shoot. It is always a dicey proposition when an actress works with a star or director—both, in this case—with whom she has an offscreen relationship. Keaton appeared in more scenes than any other actor save Beatty, and many of them were difficult ones, where she had to assay a wide range of feelings, from romantic passion to anger, and deliver several lengthy, complex, emotional speeches." George Plimpton once observed, "Diane almost got broken. I thought was trying to break her into what Louise Bryant had been like with John Reed." Executive producer Simon Relph adds, "It must have been a strain on their relationship because he was completely obsessive, relentless."