Kate chose an elegant Alexander McQueen outfit for her visit to Britain's World War II code-breaking site in Buckinghamshire. She had previously worn the silk blouse and pencil skirt in 2011, on a visit to Summerfield Community Centre in Birmingham.
Duchess Kate arrives for a very special visit to Bletchley Park
Records show that her paternal grandmother Valerie Glassborow - who died in 2006 at the age of 82 - worked as a Duty Officer at Bletchley Park during WWII.
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The hut where Valerie worked, Hut 16 - now named Hut 6 - was part of the recent restoration project at the park. It meant Kate was able to see first-hand the building where her grandmother was based.
During her visit, Kate was pictured deciphering a morse code message using a replica radio that was used at Bletchley Park during WWII.
She also received a fascinating insight into her grandmother's wartime experiences when speaking to Lady Marion Body. Marion worked alongside Valerie and her twin Mary, and was with the sisters during the moment they heard the war in Europe had ended.
Kate's tour of Bletchley Park marked the completion of a year-long restoration project, which has seen the buildings returned to their WWII appearance.
The Duchess got the chance to view new interactive exhibitions and meet with those involved in the project, as well as former code-breakers, before planting a tree to commemorate her visit and the completed restoration.