Twilight sat on the stool in the school infirmary and slowly swung he lower legs back and forth. She always felt uneasy being here even if it was for a scheduled visit. Behind her the door to the head nurse office opened. The young mare turned started to say hello Fit n' Hardy the school nurse when the words died on her lips.Instead of the usual slightly rotund earth pony who ran the infirmary Twilight Sparkle watched as her lifelong mentor and Co-Ruler of Equestria Princess Celestia came walking over to her in an outfit like she'd never seen Fit n' Hardy wear. Come around Celestia stopped in front of the unicorn. Then with a smile on her face she addressed her pupil."Hello Twilight! Thank you for coming today. How are we feeling today?"The violet unicorn made slight gurgling noise, then after a couple seconds she spoke. "Your Highness. What are you doing here?" Celestia smiled. "Well, Fit n' Hardy is unfortunately under the weather. Food poisoning or something. And all of her assistants are off at a medical conference today. Since her planned schedule was very light today I've decided to sub in for her today!"Twilight nodded her head. "Okay. I don't mean to be disrespectful your highness but are you qualified to perform this job?"Celestia giggled. "Oh Twilight! When you've lived a thousand years you become qualified in many, many things." "Um, okay, but your Highness why are you wearing that outfit? It's, uh, um, not, well, standard issue."Celestia looked down at it and sighed. "Yes it is not standard regulation. But imagine my frustration when I discovered that they had no standard uniforms in my size! However I felt I should wear something that was appropriately themed for the role I am fulfilling today. So I improvised. This is a costume I wore to a Nightmare Nights ball a few years, and it still fits!"Twilight's brain stripped a couple of gears as it pondered the concept of her Highness wearing this at a ball. After a few seconds she succeeded in reengaging the clutch to her brain and coherent thoughts started forming again in her brain.Ignoring Twilight dumbstruck look on her face, Celestia reviewed the paperwork on her clipboard. "Now apparently you are here for your annual physical. Please follow me back to the examination room. There I'll have you undress and we can begin."The young mare made a sound like somepony stepping on a small rodent. Next in my series of anthro nurse ponies so I decided to get one princesses done right away. More to come.I hope you like what you see. Please help make more art like this possible by supporting me at Patreon