Queen Elizabeth's first ever post on Instagram is blowing up which is totally impressive ... considering it's just a boring old, OLD letter.
QE2 didn't even remember to add #latergram or #throwbackthursday when she hit the share button. Naturally, there was plenty of royal fanfare for the moment ... they had an actual ceremony for it at London's Science Museum, and she got cheers and applause when a right proper English dude announced, "It's worked perfect."
As for what the Queen posted to The Royal Family's account ... it's an 1843 letter written by computer pioneer and mathematician Charles Babbage to Queen Victoria's husband, Prince Albert.
The Queen wrote in her caption ... "In the letter, Babbage told Queen Victoria and Prince Albert about his invention the 'Analytical Engine' upon which the first computer programmes were created by Ada Lovelace, a daughter of Lord Byron."
(*EYEROLL*) Can't wait to see her #MCM.
The monarch signed off like a real newbie, Elizabeth R -- and already has nearly 60k likes. Start the countdown to her first flat tummy tea deal.