Kate Middleton channels Blair Waldorf in a Stella McCartney pussy-bow dress and headband for baby Archie's christening

The adorable baby Archie was naturally the star of the show at his christening yesterday.

But winning in the style stakes for the occasion at Windsor Castle was his aunt Kate Middleton.

One of the official photographs released by Prince Harry, 34, and Meghan Markle to mark the baptism shows the Duchess of Cambridge, 37, seated beside new royal parents and their eight-week-old son.

The mum-of-three is wearing a pink pussy-bow Stella McCartney dress, and accessorised with matching red heels and a statement headband.

READ MORE: Meghan and Harry release baby Archie's christening photos

She finished off her elegant ensemble with pearl earrings which once belonged to Princess Diana in a sweet tribute on her grandson Archie’s special day.

The Duchess’ outfit received numerous plaudits, and lead many royal style fans on Twitter to compare her to the ultra-fashionable Gossip Girl character Blair Waldorf.

One person wrote: “Kate looks like Blair Waldorf.”

Another commented: “Duchess Kate was truly giving off #BlairWaldorf vibes at #ArchiesChristening”

A third shared: “Kate channeling her inner Blair Waldorf is the best thing I’ve seen all day.”

READ MORE: Royal baby Archie's godfather named as Prince Harry's school friend Charlie van Straubenzee

In particular, social media users loved Kate’s headband in the family portrait - which also featured Prince William, Prince Charles, the Duchess of Cornwall, Meghan’s mum Doria Ragland and Princess Diana’s sisters Lady Jane Fellowes and Lady Sarah McCorquodale.

One person noted: “I think Kate’s making headbands popular again!!”

Another added: “I need Kate’s headband.”

A fourth admitted: “I’m living for the fact Kate wore a headband #RoyalFamily.”

READ MORE: Prince William looks 'sour' and 'not amused' in royal baby Archie's christening photos

The Duchess of Sussex, 37, also looked stunning in a bespoke midi-dress by Dior.

Her little boy wore the traditional Honiton lace christening gown, that has been worn by nine other royal children including Prince George, Princess Charlotte and Prince Louis.

It is an exact replica, made by the Queen’s dressmaker Angela Kelly, of a gown commissioned by Queen Victoria for the baptism of her eldest daughter Victoria in 1841.

The original gown - which was used by both Prince Harry and Prince William for their christenings - was worn by more than 62 royal babies and several monarchs during its service, before the Queen decided it had become too delicate.

READ MORE: Royal fans believe baby Archie already has Prince Harry's 'red hair' in christening family photo

Archie was christened in the private chapel at Windsor Caste in front of fewer than 30 guests yesterday morning.

In accordance with royal tradition, The Lily Font and water from the River Jordan were used during the service, which was officiated by the Archbishop of Canterbury, the Most Reverend Justin Welby.

The Duke and Duchess of Sussex have decided to keep certain details of the baptism private - including the names of their son’s godparents.

Along with the portrait featuring Kate, they chose to release another image, of the two of them with their little boy in the Rose Garden, to Instagram.

The post - in which they thanked the public for their “kindness in welcoming their first born and celebrating this special moment” - has already received more than two million ‘likes’.

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