Kate Middleton glows in lilac dress as she returns from maternity leave

The Duchess of Cambridge attended her second formal occasion post-maternity leave. She wowed fellow attendees with a dress she's actually worn before.

The Duchess and Prince William went to the first Global Ministerial Mental Health Summit on Tuesday earlier this week. The summit aims to improve mental health on an international scale through widespread discussion.

Kate stunned in her lilac A-line Emilia Wickstead dress. The dress is coincidentally nicknamed the "Kate."

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The mother of three accessorized with a crocodile Aspinal of London tote handbag. She completed the look with Gianvito Rossi's suede stilettos as well as silver earrings.

Her hair was let loose and slightly curled towards the end. Her natural makeup showcased brown eyeshadow, light mascara, and nude lipgloss.

According to Hello Magazine, Kate's first appearance in the fitted dress was during for an appearance in Hamburg during Cambridge's Royal Tour of Poland and Germany last summer.

The event yesterday was littered with political figures, experts, and policymakers. One of the goals is to remove the stigma associated with mental health.

Kate and William work through their Heads Together campaign to advocate for the subject.

Priority is given to working towards putting mental health on the same level as physical health.

The first event Kate stepped out for since finishing her maternity leave last Tuesday was the Sayers Croft Trust.

Prior to that, she had made a cameo appearance at the Wimbledon final in the summer.

The 36-year-old wrote an op-ed in the Huffington Post UK regarding the significance of ending the mental health stereotypes among both children and adults.

She is set to make another appearance on Wednesday when she will be visiting the Victoria & Albert Museum as a royal patron of the institution.

She will be responsible for opening a new Photography Center at the museum.

In a royal coincidence, Pippa Middleton wore an unusually similar maternity outfit earlier this week to Kate's maternity wear when she was pregnant with Princess Charlotte in February 2015.

Pippa, who is reportedly expecting her first baby's arrival later this month, was seen adorned in a purple print dress as she strolled through Chelsea, London.

The Claudie Pierlot frock was patterned with tiny paisley prints. The bottom part was designed in pleats. She coupled the dress with some white sneakers.

Her accessories were a nude tote and she spoke on the phone while carrying a COS shopping bag.

Kate wore a very similar outfit three years ago. Her dress featured a violet floral print that gave off a bolder look. The outfit was also knee-length with long sleeves.

In comparison to her younger sister Pippa, Kate wore navy pumps and a small clutch for her visit to London's Goring Hotel at the time.

Pippa also rocked a stunning coat early this month as she exited the KX Gym in Kensington.

The dark navy wrap dress not only showed off her high fashion sense but also her bludgeoning bump.

The royal has been quite vocal about the benefits of exercising while pregnant and just how enjoyable the experience is.