It gets its name from the sweet diamond knots seen at the top of the item, which adds a romantic edge.
A youthful piece, it is one we are likely to see Kate wearing for some time to come, before she moves on to grander tiaras when she is Queen Consort.
Speaking about the potential value of the diadem, Deborah Papas, gemmologist and jewellery expert from Prestige Pawnbrokers of Channel 4’s Posh Pawn said: “One of my favourite quotes is from Keats ‘A thing of beauty is a joy forever’.
“This is certainly true of this magnificent tiara. I am not surprised the tiara was prone to give headaches! It is large and made from platinum, which is a dense metal and would be at least 95 percent pure, giving a heavy mount to start with.