Another amazing feat done by the Duchess of Cambridge! Known as the "Kate effect," the Duchess made another simple creation stand out, to the point where it's considered sold out. A day after attending the premiere to "Mandela: Long Walk to Freedom," the $35 sparkly, crystal-bead Zara necklace has sold out on Zara's website.

Kate paired this with a Roland Mouret gown and a simple loose ponytail which contradicts her look from the previous evening - she wore the fabulous and extremely expensive family tiara heirloom.

The "Kate effect" has been going on for a while now and has favored many relatively smaller designers whenever Kate decided to wear their creations. Remember her engagement dress in 2010? That blue Issa London wrap dress sold out immediately after 24 hours and demand right now is still going strong.