Queen Elizabeth wore this uniquely shaped hat (does anyone else see a flying saucer?!) during state visits to Japan and Mexico in 1975. She repeated it on June 29, 1977 on a visit to Portsmouth during her Silver Jubilee tour of Great Britain.
Embed from Getty Images
Embed from Getty Images
Image from Getty as indicated
Royal Hats 
I think there may be a bow.
It looks almost like a Breton. From the first picture I was also even wondering if there was netting of some sort stretched over the crown to the brim, creating the ‘saucer’ effect’. Or just the effect of the particular lighting? Oh, for some different angles!
Peak 70s again; the tailoring on that coat! I like the hat, you can see the shift to plain shapes with a bit of froof is now complete.
Gosh, this is an unusual one for Queen Elizabeth. I love it from the front and it’s a pretty soft shade of green but the ‘flying saucer’ part is not my favourite. Can’t quite see if it has a bow on the back.