Royal fans with an eye for detail have spotted what appears to be the Princess of Wales enjoying a dance at her brother's wedding.
Kate Middleton's younger brother James, 35, shared a photo of him and Carole Middleton, 68, taken on his 2021 wedding day on his Instagram account to mark Mother's Day on Sunday.
In the previously unseen photo, the youngest Middleton sibling is pictured hugging his mother during an evening reception after he tied the knot with Alizée Thevenet.
The eagle-eyes fans noted that Kate, seen wearing a short-sleeved white dress, appears in the background of the sweet snap.
It was reported at the time of the nuptials that the Prince and Princess of Wales - then the Duke and Duchess of Cambridge - took their three children to attend their uncle's wedding at the Chateau Leoube, an exclusive vineyard in the village that produces some of France's finest rose wine.
A glimpse of Kate! James Middleton, 35, who lives in Berkshire, shared a snap of himself and mum Carole Middleton, 68, on his Instagram account to mark Mother's Day on Sunday
James and Alizée walked down the aisle in Bormes-les-Mimosas, Provence in September 2021, in a ceremony attended by 50 guests.
The couple were engaged in September 2019 but had to delay their nuptials twice because of Covid, before finally getting hitched two years later.
In the snap, a beaming James can be seen hugging his mother Carole on what appears to be the evening of his wedding day. Older sister Kate can just be seen in the background of the picture, talking to another guest.
The royal is wearing a white short-sleeved cotton dress, and her hair is styled in natural-looking wavy tresses. Her appearance in the picture didn't go unnoticed with royal fans, with one asking: 'Last on the left, is Kate dancing with a man?'.
Mr Middleton and Miss Thevenet, a trilingual French financial analyst, also in her 30s, met in 2018 when his cocker spaniel, Ella, approached her at a private members' club in London.
The couple, who announced their engagement in 2019, had originally planned to get married in May 2020 but they were twice forced to push back the date.
James said in a post on Instagram in September of 2020: 'It's a year since I asked Alizée to marry me… what a year it's been!
Eagle-eyed royal fans spotted Kate Middleton in the newly surfaced pictures of James' French nuptials
Summer wedding: Announcing his marriage with a picture of him and bride Alizée on Instagram in September 2021, James gushed: 'Words cannot describe how happy I am'
'Two homes, lockdown, two attempts at a wedding, a litter of [dog emoji], launching of new company @ella.co, a beard shave and much more but the best part is that I get to share it with you @alizeethevenet and I can't wait to take on whatever the future holds for us.'
The Prince and Princess of Wales attended the wedding along with James' other sister, socialite Pippa, and her businessman husband James Matthews.
Their parents Carole and Michael Middleton, and James beloved dogs, Luna and Mabel, also watched them walk down the aisle.
Announcing his marriage with a picture of him and bride Alizée on Instagram shortly after the ceremony, James said: 'Words cannot describe how happy I am.'
A source in the French village told MailOnline at the time: 'The wedding party was held at a Chateau Leoube. It is one of the most exclusive vineyards in the area.
'Chateau Leoube makes exceptionally good wine, particularly the rose, which is known throughout France and overseas.
'So it was only natural that the guests were served with Chateau Leoube wine, which they drank when they toasted James and Alizée. Many bottles of wine were drunk. Everyone had a good time.'