You can still have chemistry on screen without getting on with the person. But it just makes your job a lot easier if you don't have to gird your loins, if that's not quite the right phrase, every time you're going to do a scene with that person.
“I had been plunged into a different world. I found myself spending half my time answering weird questions on book tours in the Midwest. People would stand up and explain to me the situation in their office and ask me whether they should resign or not.”
“But I want you to know that what I'm doing here I'm doing as a ballplayer, a major league ballplayer.”