In a large stock pot set over medium heat, whisk together the chicken stock, cream of chicken soup, lemon juice and lemon zest.
Stir in the orzo and chicken then bring the mixture to a boil. Reduce the heat, cover the pot, and cook it until the orzo is tender and the soup is warmed through, about 8 minutes. (See Kelly’s Note.) Taste and season the soup with salt and pepper.
Serve the soup garnished with fresh dill and a sprinkle of freshly grated lemon zest (optional).