The Diamond Jubilee marks 60 years of England's Queen Elizabeth II on the throne and, as part of the mammoth celebrations taking place in London, Robbie will be taking to the stage at Buckingham Palace tomorrow evening, alongside a whole host of pop's royalty!
The music spectacular will feature an array of stars from the last sixty years, coming together from the worlds of rock, pop and classical music, to entertain Her Majesty the Queen and the royal family, and of course all those lucky enough to have bagged tickets via a ballot earlier this year.
The BBC will be broadcasting the concert live on Monday evening from 19:30 BST on BBC1 and BBC Radio 2 so be sure you're in front of a TV or by the radio… you don't want to miss this!
Are you going?
If you're lucky enough to be going to see Robbie on stage tomorrow, we want to see your photos. Get on Twitter and tweet your pictures to @robbiewilliams, we'll retweet the best ones so that everyone can stay tuned to the excitement, wherever they are!