Prince William, Kate Middleton Smiling in First Outing Since Prince Harry's Memoir Release

Prince William and Kate Middleton are lookin' as unbothered as they can in their first public appearance since Prince Harry's bombshell new memoir aired out a ton of royal family dirt -- much of it related to his brother.

The Prince and Princess of Wales were smiling from ear to ear Thursday as they left Windsor Castle and took off to Liverpool ... where royal fans/subjects greeted them at the opening of a new hospital.

While their faces say everything's peachy keen, Harry's "Spare" has to be on their minds. As it's been WIDELY reported, Harry unloaded his side of the royal family drama in the book, revealing he and Wills have been bitter rivals since even before Meghan Markle came into the picture.

Of course, the Duke of Sussex says things got even more heated post-Megan -- claiming big bro William grabbed him by the collar, ripped his necklace, and knocked him to the ground during a 2019 fight sparked by William allegedly calling Meghan "difficult" and "rude."

It is an interesting coincidence Kate and William are in Liverpool ... birthplace of The Beatles. In better days, at least publicly, royal watchers referred to Harry, Megan, William and Kate as the new Fab Four.