The Princess of Wales appears to have been spotted in a never-before-seen Middleton family photo shared by her brother.
To mark Mother's Day and to pay tribute to mum Carole, James Middleton posted a touching snap that appeared to have been taken at his wedding in France last summer.
In the photo, James can be seen wrapping his arms around Carole as they smile for the camera, as other guests appear to party in the background.
In the caption, James lovingly wrote: "You make my world go around. Happy Mother's Day to all of the mothers out there and especially this one."
And according to some eagle-eyed fans, one of those in the background is sister Kate, who appears to be wearing a simple dress with her hair loose around her shoulders.
One commented: "Lovely pic, I'm sure I can see Kate to the left in the background."
While another said: "The one in the back looks like Kate."
James married wife Alizée Thevenet in a ceremony in the south of France last year, which was attended by Kate, Prince William and their three children Prince George, Princess Charlotte and Prince Louis.
He added Prince William and Kate were there but "did not want to steal the show from the newlyweds" and explained the wedding had been organised with the "utmost discretion".
James' tribute came after heartwarming new pictures of Kate alongside Prince George, Princess Charlotte and Prince Louis were released for Mother's Day.
The first image shows Kate sitting in a tree with her children and is accompanied with the words “Happy Mother's Day from our family to yours” along with a red love heart. Another photograph shows a smiling Kate as she plays with Louis in her arms.
They are all casually dressed and smiling into the camera and the snaps appear to have been taken at the same time as the Christmas card photo they released last year.
Meanwhile, King Charles remembered his mum the late Queen on the first Mother's Day since her death.
A poignant message celebrating all mothers was posted online alongside treasured images which showed Charles as a beaming baby standing on the Queen’s lap.
Another snap showed an adult Queen Camilla smiling as she stands behind her elderly mother Rosalind Shand, who died in 1994 at the age of 72 after a long battle with osteoporosis.
The Twitter post was accompanied by the message: “To all mothers everywhere, and to those who may be missing their mums today, we are thinking of you and wishing you a special #MothersDay."
