"I think with Mary that relationship is still there but it's changing," she says. "Michelle and I are great friends and we just love working together. It's almost easier because there's no half apology afterwards. I can call her a slut and mean it, sort of thing, as I did in the first series. We really laughed that day because there isn't any part of me holding back. We respect each other as actors and we really give over to that, and then fall about laughing.