I believe it was the 9th night…. But I would say check the celebrity app, go the the MDR, then menu, there you will be able to see the menu for each day of the cruise….
I sailed CC at the end of Feb, Prime Rib was on the menu twice and lobster once.... On Lobster night, our waiter recommended ordering an entree and adding on a lobster tail.... No charge... Only upcharge if you ordered the Lobster dinner and added on another tail....