First picture of Kate since her operation is released on Mother's Day

The photo of Kate and her children, taken by the Prince of Wales in Windsor earlier this week, was posted on social media to mark Mother's Day.

In the post she said: "Thank you for your kind wishes and continued support over the last two months.

"Wishing everyone a Happy Mother's Day. C."

The picture shows Kate sitting in a chair with her arms around Princess Charlotte and Prince Louis who are on either side of her, with Prince George standing behind, as all four smile at the camera.

The photo of the princess is the first released since she was admitted to the London Clinic - the private hospital where the King underwent treatment for an enlarged prostate - for a planned operation on January 16.

Charles, 75, visited his daughter-in-law's bedside after being admitted himself on January 26 - the 11th day of Kate's stay.

She was also visited by her husband, William.

Kate left the hospital on January 29 - almost two weeks later - and returned to Adelaide Cottage in Windsor.

Details of the princess's condition have not been revealed but Kensington Palace previously said it was not cancer-related and that Kate wished her personal medical information to remain private.

The 42-year-old future queen was last pictured in public during a Christmas Day walk in Sandringham, Norfolk.

Kate is not expected to return to official duties until after Easter, and William, 41, had temporarily stepped back from his royal role to juggle caring for her and their children.

He carried out his first public engagements since her surgery in early February.

Kate's parents, Carole and Michael Middleton, and siblings, Pippa Matthews and James Middleton, were expected to be hands-on in helping the Waleses.

Separately on Sunday, Earl Spencer – the brother of Diana, Princess of Wales – revealed that he was sexually “preyed” on by a female member of staff at his boarding school.

The claim came in an extract from his memoir, which has been serialised in the Mail on Sunday.

He says he was abused by an assistant matron at the school when he was 11, leaving him with such trauma that he self-harmed over the notion she may leave the school.

Earl Spencer wrotes: “There seemed to be an unofficial hierarchy among her prey… she chose one boy each term to share her bed and would use him for intercourse.

“Her control over mesmerised boys was total, for we were starved of feminine warmth and desperate for attention and affection.”

As a result of the experience, Earl Spencer says he lost his virginity to an Italian prostitute at the age of 12.

He was also beaten by teachers, and described his experience of the school as “hellish”, writing: “Many of us left Maidwell with demons sewn into the seams of our souls.”

His book, A Very Private School, it due to come out on March 14.