Every outfit Meghan Markle wore during her NYC tour

Watch: Meghan Markle's monochrome outfit is Autumnal perfection.

Meghan Markle has treated fans to a glimpse of her working wardrobe on a tour of New York with her husband Prince Harry.

In one of their first joint appearances since welcoming their daughter Lilibet, three months, the Duke and Duchess of Sussex flew from their home in California to New York City where they undertook a series of engagements, culminating at the Global Citizen Live Concert, where they joined a number of A-List names in promoting vaccine equality.

And while the three day tour caused plenty of talking points, for fashion fans it was all about what the Duchess was wearing.

Kicking off the brief tour on Thursday morning with a World Trade Centre memorial visit, the Duchess looked sombre yet sophisticated in an Emporio Armani navy coat with Aquazzura pumps.

According to fashion and lifestyle expert, Karine Laudort, Aquazzura is a shoe brand the Duchess has worn several times before, including for the announcement of her engagement and on her wedding day.

Underneath the cosy coat she wore matching wide-legged trousers and a simple dark polo-neck top.

Subtle make-up and a neat, low bun finished the look. "This navy ensemble is effortlessly chic, comfortable and perfectly fitting for a formal engagement," Laudort adds.

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Later that day, she and husband Prince Harry stepped out once again to visit the UN headquarters to meet with Ambassador Linda Thomas-Greenfield and discuss racial justice, mental health awareness, and the COVID-19 pandemic.

For the occasion the Duchess switched up her outfit, by swapping her trousers for a pencil skirt by Roland Mouret and changing into a classic camel coloured coat by Max Mara.

To compliment the luxe look, Markle added tortoiseshell sunglasses from Valentino and a mini bag from accessories brand, Valextra, which Laudort believes adds some sophistication to the look.

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On day two of the tour, the couple dropped into Harlem where they visited a local school and the Duchess read excerpts from her book The Bench to a group of pupils.

In a mood change that marked the more relaxed feel of the visit, Markle stepped out in an all-maroon ensemble, consisting of a coat, another pair of wide-leg trousers and matching heels, in a look that gave us all the Autumn vibes.

The Duchess' oversized jacket is a reversible cashmere coat by Italian luxury label Loro Piana, with the former royal keeping the overall look paired-back by keeping the colour palette of the entire outfit to similar maroon hues, teamed with her trusty Manolo Blahniks.

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Markle accessorised with a Cartier 'love' bracelet which seemed to be her go-to jewellery for the entire trip.

"For this particular look Markle went back to one of her staple monochromic looks - a power suit with a wide coat and long floaty trousers," explains Laurdort.

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Saturday saw the Duchess of Sussex wear two outfits, starting with her second visit to the UN.

First up was an all beige offering featuring wide-legged trousers by Max Mara and a fitted beige shirt, which Markle teamed with a re-wear of the Max Mara 'Lilia' cashmere coat.

Later that day, the Duchess changed into a white mini dress dress in an appearance at the Global Citizen Live concert in Central Park, where she and husband Prince Harry addressed the crowd in a discussion about vaccine equity.

The Duke wore a sharp black suit for the occasion, while Markle opted for an embellished white short-sleeved mini dress by Valentino.

She accessorised the knee-skimming dress with black heels and a Lady Dior bag, sweeping her hair back into a low ponytail.

"What a better and classier look for her return to the spotlight after several months of absence," says Laudort.

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So what did we learn from the Duchess' NYC wardrobe?

For celebrity style expert Miranda Holder, the stand-out theme was seeing Markle make a return to power dressing.

"Meghan is no stranger to power dressing, and her outfits definitely had a corporate feel to them and would have not looked out of place on set back in the series ’Suits’ which made her famous," she explains.

Also evident was the Duchess' desire to embrace a colour block look.

"Dressing top to toe block colour - known as Monotone - makes you appear taller and more imposing, and is a guaranteed way to to stand out from the crowd and make an impression," explains Holder.

"It also felt appropriately ‘royal’ as we are used to members of the British Royal Family dressing in a single tone, just think of the candy coloured hues the Queen looks so good in.

"The wine tones and shades of camel and caramel compliment her raven hair and warm skin tone perfectly, although the black to me felt a little sombre and severe."

Holder also expects something of a 'Meghan Effect' with items of her tour wardrobe expecting to sell out quickly.

"Like her sister-in-law, Kate, Markle can literally transform a fashion brands credentials overnight by wearing their pieces," she explains.

"Fashion houses will be extremely keen for their collection to be seen on such a high profile ‘model’, and its is highly likely that Meghan will have been working with a stylist in preparation for this trip to carefully compile these looks, with many garments being loaned or gifted by the designers themselves."