Princess Elizabeth attended the rededication of the Festival Church, St John-the- Evangelist on April 26, 1951 in a brimless draped hat with dramatic fan at the side. She had worn the hat in October the previous year for Princess Anne’s christening.
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Royal Hats 
Found one more siting:
April 5, 1951(?): On Gozo (an island near Malta)
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I forgot to add 2 minutes of movement.
Happy weekend, hat lovers. (I think I gave up the wrong thing for lent – It’s only 1pm here, and I could use a Boodles G&T!)
How many ways do I love this hat! Any info on the brooch? It’s lovely.
Only one other outing for this chapeau could be found so far, in living b/w.
May 4, 1951: Festival of Britain
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A replacement hat came on the scene for many appearances.
April 16, 1951: Rome
May 18, 1951: Hastings
May 26, 1951: Windsor Castle
June 8, 1951: Royal Worcester
June 13, 1951: Royal Ascot
August 18, 1951: Tennis Party
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This is such a sweet hat. The fan embellishment on the one side just adds a little uniqueness taking it out of the ordinary. I believe it was in a beautiful sky blue. An interesting choice for the christening of a baby Princess! In just a very few months from these photographs Princess Elizabeth would become Queen.