The very important hidden meaning in Kate Middleton's latest recycled outfit.

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Kate Middleton is BACK.

Just less than six months since giving birth to her and Prince William’s third child Prince Louis, the Duchess of Cambridge has ended her maternity leave and is back conducting royal duties.

Yesterday, she and William attended their first official outing together since her return at the Global Ministerial Mental Health Summit in London. The event fell a day before World Mental Health Day (October 10, aka today), a cause near to the Duke and Duchess’ hearts.

Kate wore a beautiful lavender Emilia Wickstead dress worth almost $2500AUD and yes, you have seen it before. If we owned a dress that cost that much, we’d probably wear it everyday but Kate was last seen in the dress during a tour of Germany in July 2017.

Given the event, there may have been a hidden meaning behind why Kate chose to give this particular outfit another whirl.

You see, Color Psychology  states the colour lavender can have the same effect as the flower it is named after.

Lavender is mentally associated with healing, relaxation and cleanliness. It encourages calmness and is useful for invoking a relaxed, meditative state, making it the perfect colour choice for an event advocating for global commitments to share effective and innovative approaches to mental health.

Kate and William are huge advocates for mental health. They, together with Prince Harry, spearhead Heads Together, a campaign to tackle stigma and change the conversation on mental health with fundraising for a series of innovative new mental health services.

In 2016 Kate wrote an op-ed for the Huffington Post about the importance of removing the stigma.

"[William and I] hope to encourage George and Charlotte to speak about their feelings, and to give them the tools and sensitivity to be supportive peers to their friends as they get older. We know there is no shame in a young child struggling with their emotions or suffering from a mental illness," she wrote.