The leading actresses of the hit U.S. show have faced reports they don't get on, with Cattrall and Parker at the centre of speculation about a rift.
The stars have previously brushed off the rumours, claiming they are pals who maintain a professional working relationship.
But now the leading ladies have opened up about their onset struggles, admitting they often clash when they're stressed and tired during the long working days.
Parker says, "When you're on set, you're working 90-hour weeks, you're never home, you're exhausted. There are times when all of us have been sensitive and sometimes feelings get hurt. But I don't have any regrets about how I've treated people."
Nixon adds, "It hasn't always been smooth sailing. But the idea that we're somehow adversarial is ludicrous."
And Cattrall insists despite their occasional bickering, they make jokes to lighten the mood: "Nineteen-hour workdays are stressful, whether you're driving a truck, working in a coal mine or on a set and trying to be your brightest at 4 o'clock in the morning. But there's a camaraderie that happened through all of that... The chemistry among the four of us is very strong."