Playing no-nonsense nanny Mary Poppins — famously described as “practically perfect in every way” — seems to have gone to Emily Blunt’s head. A source on the set of next year’s sequel, Mary Poppins Returns, says that in between takes the British beauty carried on in character, organizing things, cleaning up messes or telling others to and reminding people of the time so they could stick to the filming schedule. “She became downright demanding, strutting around all prim and proper,” says the insider. “She was never mean, but she adopted this stiffness and air of authority. And the funny thing is, it worked! People started anticipating tasks that needed doing before Emily could get around to pointing them out.” No word on whether a spoonful of sugar was involved.