Royal blue Kate looks stylish and elegant in an

Royal blue Kate looks stylish and elegant in an Alexander McQueen coat as the royals attend church service at Sandringham on Christmas Day

The Princess of Wales looked suitably regal in a rich royal blue as she celebrated Christmas Day with the extended Windsor family at Sandringham yesterday.

Kate held her daughter Charlotte's hand on the way to the annual Christmas service at St Mary Magdalene Church and her key piece was a long Alexander McQueen coat with fabulously structured shoulders and a cinched waist. Simple, stylish, elegant… We've come to expect nothing less.

She paired this with a navy turtleneck, custom £1,180 suede knee-high 'Glen 85' boots by Gianvito Rossi and a custom matching royal blue headpiece. The dramatic pillbox-style felt hat, designed by London-based milliner Juliette Botterill, was decorated with an elegant, stylized bow and crossed quill embellishment.

The look was completed with her linked diamond-set sapphire earrings from her late mother-in-law Princess Diana's jewelry collection.

It was the queen of tone-on-tone dressing at her best.

Elegance: The Princess of Wales and Princess Charlotte, eight, at Sandringham yesterday

Elegance: The Princess of Wales and Princess Charlotte, eight, at Sandringham yesterday

In step: King and Queen Camilla.  Below: Sophie, Duchess of Edinburgh in a feathered fedora

In step: King and Queen Camilla. Below: Sophie, Duchess of Edinburgh in a feathered fedora

Kate, who has been known to wear the same clothing in multiple colors, also owns a green version of this gorgeous Alexander McQueen coat and a black version of the hat she wore at the St. David's Day parade in March this year Welsh Guard wore.

Kate has adhered to the formal Christmas dress code since she first joined the family at Sandringham in 2011, the same year she married Prince William at Westminster Abbey. On this first occasion she wore a maroon coat dress and matching hat by Jane Corbett.

In the 12 years since, this formula of a tailored coat with matching headwear has been refined and repeated, and this may be the strongest iteration yet.

Her family coordinated their outfits this year. The future king and his eldest son, 10-year-old George, also wore blue, while eight-year-old Princess Charlotte wore a fern green double-breasted coat with a velvet collar – similar to the shade her mother wore last year – with navy tights and matching ballet flats.

Meanwhile, five-year-old little Prince Louis joined the family in the most festive outfit of all – a navy peacoat over green and blue tartan trousers, £60 from Trotters – a change from his usual shorts and knee socks.

He adorably clutched the hand of his older cousin Mia Tindall, nine, who was also on her way to the service with her parents Zara and Mike Tindall and her five-year-old sister Lena.

The Duke and Duchess of Edinburgh attend the Christmas Day morning service at St Mary Magdalene Church in Sandringham, Norfolk

The Duke and Duchess of Edinburgh attend the Christmas Day morning service at St Mary Magdalene Church in Sandringham, Norfolk

The Prince and Princess of Wales weren't the only ones coordinating. The King and Queen wore complementary colors with Camilla in a beige long coat by Anna Valentine that we've seen many times before. She wore a blue paisley silk dress with beige boots and a Philip Treacy hat with feather detail. The king reflected her with a classic camel coat.

The ever-elegant Sophie, Duchess of Edinburgh was spotted in a coat dress by Claire Mischevani, a British designer who has become a firm favorite among the royals.

Sophie's tweed piece was adapted from a khaki crepe design – also with a bow detail at the neckline – available online for £1,145. A fabulously festive choice, finished off with a fedora from Hicks & Brown worth £95.

For the second year in a row, Andrew, the disgraced Duke of York, walked with the family to church. His ex-wife Sarah, Duchess of York, made her first public appearance at Sandringham in years. She walked alongside her ex-husband in Holland Cooper's Dowdeswell coat (£799) in emerald green, a traditional choice for the Sandringham service, teamed with ankle boots and a matching jeweled clutch.