Pippa Middleton delights in sleek coat dress for rare appearance at coronation

On undoubtedly one of the biggest days of her royal life, the Princess of Wales had some very special support at the coronation of her father-in-law, King Charles III. Princess Kate was joined by her sister Pippa Middleton and brother James Middleton on May 6 for the milestone moment in British history.

The sibings were among guests at the ceremony, which was presided over by the Archbishop of Canterbury and additionally broadcast live on television.

WATCH: CORONATION DAY is here!

Princess Kate’s sister opted for a subtle dose of elegance with her outfit. The mother-of-three arrived at Westminster Abbey wearing a Claire Mischevani Alais serene lemon yellow coat dress. Featuring a tailored cit, long sleeves and sleek lapels, the sophisticated piece was perfectly paired with delicate heels and a simple clutch bag in a matching shade of yellow.

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Pippa and James Middleton arrived at Westminster Abbey in central London ahead of the coronations of Britain's King Charles III and Britain's Camilla, Queen Consort

Pippa wore her brunette locks tied back in a twisted style and opted for a glamourous makeup look, which consisted of a honey-hued complexion, a dusting of rose-tinted blush, a flutter of mascara and a glossy lip.

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James looked smart beside his sister, sporting a matching yellow waistcoat and charcoal grey trousers.

Princess Kate's sister wore a sunny shade of lemon yellow

The siblings delighted crowds with their rare appearance, walking side-by-side as they joined family members the Prince and Princess of Wales at the service.

Michael Middleton and Carole Middleton joined daughter Pippa Middleton for the event

With that in mind, the King made the sweet decision to invite Kate’s family to the grand coronation. They have previously been asked to join the royal family at church in Sandringham and were spotted at the Queen's Platinum Jubilee Party last June.

Carole and Michael also joined senior members of the royal family at the Queen's funeral and committal service in September.

Shop the best coat dresses

Karen Millen Tailored Crepe Asymmetric Pleated Coat Dress
Karen Millen Coat Dress
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This sophisticated dress has a military vibe, with double breasted fastening, notched collar and long sleeves. Note the flowing full skirt and midi hemline.

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Phase Eight Sienna Tuxedo Dress
Phase Eight Sienna Tuxedo Dress
Phase Eight Coat Dress
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Phase Eight's coat dress is spot on for a wedding; the traditional fabric covered buttons are an elegant detail, while the classic boat neck is flattering whatever your figure.

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Gina Bacconi Lulu Jacquard Dress & Coat
Gina Bacconi Lulu Jacquard Dress & Coat
Gina Bacconi Coat Dress
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This coat dress is a great mother of the bride outfit; the mint shade will flatter warmer skin tones while the A-line fit is great for accentuating a small waist. The detailing is beautiful, with a jacquard style pattern all over and single button closure.
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Self-Portrait Boucle Midi Coat Dress
Self-Portrait Coat Dress
Sizes: 8 - 16
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An ultra-elegant and trendy dress from Self-Portrait, in royal-approved boucle. The off-shoulder detailing and embellished buttons give it a point of difference, too.
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Karen Millen Tuxedo Wrap Dress
Karen Millen Tuxedo Dress
Karen Millen Coat Dress
Sizes: 6-16
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This sleek blazer dress from Karen Millen is smart and sexy; the double-breasted fastening and sharp collar are giving smart vibes.
It's available in light pink and light blue, and the belt detailing will accentuate your waist and balance out the sharp shoulders.
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Royals wearing sunshine yellow:

Abdullah II of Jordan and Queen Rania of Jordan arriving at the coronation in yellow

Princess Kate during her official arrival at Norman Manley International Airport in Jamaica — Princess Kate rocked bold yellow during her official arrival at Norman Manley International Airport in Jamaica

The Duchess of Sussex arriving to meet youngsters from across the Commonwealth as they attend the Your Commonwealth Youth Challenge reception

Queen Elizabeth II watching her horse 'Fabricate' run at Ascot Racecourse

Princess Diana wearing a satin evening dress designed by Murray Arbeid

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