Happy Easter to all celebrating the day! The Duchess brought back an Emilia Wickstead design as the Cambridge family attended church at St. George’s Chapel in Windsor. 
They joined a large group of other royals that included Sophie, Countess of Wessex, Lady Louise Mountbatten-Windsor (18), James, Viscount Severn (14), the Earl of Wessex, Princess Eugenie, Peter Philips, and his daughters Isla (10) and Savannah (11), Mike and Zara Tindall and their daughter Mia (8), and the Chatto family. 
More from this Telegraph story.
The Queen, who turns 96 on Thursday, did not attend this morning’s service, as she continues to suffer with mobility issues. She will instead mark the event at the private chapel at Windsor.
The service falls on the one-year anniversary of the Duke of Edinburgh’s funeral, which took place at the same chapel on April 17, 2021.
The last Easter Mattins service to be held at Windsor took place on the Queen’s 93rd birthday, April 21 2019.
The Prince of Wales and Duchess of Cornwall are in Scotland. Princess Anne and Vice Admiral Sir Timothy Laurence have just returned from several days in Australia and Papua New Guinea.
Another view of the Duchess and Princess Charlotte. 
Below, the Tindall and Chatto families as they walked to the chapel.
Princess Eugenie and Peter Phillips with his daughters. 
Others heading to church at the chapel this morning. 
The Slough Observer reports “Staff at the castle said although the Queen was not present at the service she would be spending the day with her family afterwards.”
The Kensington Palace social media accounts offered this greeting today. 
While the Buckingham Palace account reposted the greeting from Prince Charles and the Duchess of Cornwall.
“This Easter, as always, we are reminded of Our Lord’s timeless example of goodness in the face of suffering, of courage in the face of fear, of faith in the face of despair. His light triumphed in that dark time.”
– The Prince of Wales on Easter Sundayhttps://t.co/cWF16boH8L pic.twitter.com/Bs3wIbJ8kH
— The Prince of Wales and The Duchess of Cornwall (@ClarenceHouse) April 17, 2022
Today’s service was led by the Right Reverend David Connor, the Dean of Windsor since 1998. 
The Cambridges as they left the Easter Mattins service. 
A video of departures from the church.
A wave from Kate as the @RoyalFamily leave today’s Easter Sunday service at #windsor pic.twitter.com/FF07dQCQGN
— Slough Observer (@sloughobserver) April 17, 2022
The Countess of Wessex and Lady Louise Mountbatten-Windsor. 
Data Duchess reports that Sophie wore the ‘Raquel Bea’ dress by Soler London and Jane Taylor’s ‘Greta’ hat, while Royal Fashion Police notes Lady Louise wore the Valerie Floral Midi by Hush Homewear.
Princess Eugenie and Peter Phillips. 
Princess Eugenie wore a Peter Pilotto floral print dress, with thanks to Polka Popp for that ID.
Zara Tindall shaking hands with the Dean after the service. 
Ms. Tindall wore the Mathilde Dress by LK Bennett per Polka Popp on Twitter.
Lady Sarah Chatto with son Arthur (I believe) as they left the chapel. 
Now for our look at what Kate wore today. The bespoke Emilia Wickstead design is crafted from a double wool crepe fabric and showcases the fit and flare silhouette the Duchess is so fond of, as well as a set-in waistband, peak lapels, and concealed closure.
The design was first worn for a May 2017 visit to Luxembourg. 
The Duchess has repeated ensembles for all of the Easter Sunday services she has attended at Windsor. A review of past Easter looks includes the Duchess’s 2019 ensemble, a dove grey look by Alexander McQueen first worn at 2014 Easter services in Sydney, Australia. The Duchess was expecting Prince Louis when attending Easter services in 2018, and she brought back wore a chocolate brown Catherine Walker coat seen in 2015 for St. Patrick’s Day with the Irish Guards. At the 2017 Easter service, it was also a Catherine Walker repeat of a design first worn during the 2016 Canada tour. 
Today’s repeat is similar to other Emila Wickstead designs the Duchess has worn, especially the green coatdress first noted on St. Patrick’s Day 2012. The yellow design first worn to Order of the Thistle in 2012 and again in 2016 when arriving in Bhutan has a different bodice and collar design.
The Duchess wore the Jane Taylor Diamond Crepe Pleated Headband first seen when attending church at Sandringham in January 2019. 
How the piece looked in 2019. 
She added another Emmy London ‘Natasha’ handbag to her collection, this one looks like the Duck Egg Blue style ($370) in soft kid suede. 
It looked like the Duchess wore her Rebecca Pumps ($415) in Riviera Blue, also by Emmy London. 
The earnings are the Cassandra Goad Cavolfiore Studs (£4830, about $6300 at today’s exchange rates) seen on previous occasions. The design is “inspired by the clusters of young flower stalks of the cauliflower (cavolfiore) in the market,” and each earring holds seven pearls set with diamonds in 18ct yellow gold.
VIDEO:
The Royal Family Channel offers about two minutes of coverage in this video.
The Slough Observer shows more than a minute of arrival coverage in this video.
Lovely morning at Windsor Castle as the @RoyalFamily arrive for the Easter Sunday service at St George’s Chapel. Read our full story here: https://t.co/YYySO6ooSU pic.twitter.com/s11FTRukgi
— Slough Observer (@sloughobserver) April 17, 2022
shannon
Thursday 21st of April 2022
I love this coat so much it hurts!She looks classy as ever and cute with the headband touch.
Allie
Wednesday 20th of April 2022
Does anyone know about the rings DoC is wearing? Thx! Gosh I adore this coat
admin
Wednesday 20th of April 2022
I believe she is wearing her engagement ring, wedding band, and eternity band. :)
BethE
Wednesday 20th of April 2022
I love this choice of repeat for Easter services. This shade of blue is so pretty in the spring sunshine. And, of course, Catherine always looks well in blue. I like that we get a clutch that matches the dress, but not the shoes or hat. The different color on top and bottom relieves the baby blue of the overall outfit. Wickstead pieces are hit or miss, largely based on tailoring - as others have noted. I find this one of her better pieces. Since she first wore it, the notched lapels feel a touch dated in the width and spread; the style has moved into a narrower lapel. However, they balance the flare and swing of the skirt nicely. The coat remains classic and certainly useful as styles ebb and flow.
However, we must simply talk about that headband and its styling. With a center-gathered decorative seam, it will never compliment a center hair part. Ever. The effect is shockingly unflattering on the quite impossibly beautiful Catherine. Hair trends come and go, and we are very much in the center-part phase of style right now. But one must consider the overall effect. As it was styled previously, the headband was more pleasant. That is, unfortunately, not saying much; I do find the piece odd.
Catherine has any number of white, cream, and blue hats that could have served the same purpose in offsetting the color of the coat. I can only think that she used the headband to keep the formality of her ensemble more in step with the other women who were largely in floral frocks with more traditional hats. The coat dress + headband feels at the same level where a coat dress + hat might have stood out more.
Larsa
Tuesday 19th of April 2022
I have always loved this coatdress and have longed to see it again. Easter is the perfect occasion for this piece. The color is just a lovely spring shade and the dress itself sits so prettily on Kate. I do think the sleeves seem a touch too long but it's not too noticeable. I actually didn't mind the pretty powder blue shoes or the clutch and didn't think the various blues were an eyesore. The eyesore for me is the headband. Gosh, it is not a pretty one no matter what angle you look at it from. I think the design itself and the way Kate wore it all together were just not great. Even the simplest light blue headband would've done miles more for this look than this piece. Oh well! Excited to see her with Princess Anne next week. What a rare treat. :)
Rebecca
Tuesday 19th of April 2022
I love everything about this outfit! Kate looks 5 years younger with knee-length skirts.