The uncle of the Princess of Wales has praised her as “perfect” as he entered the Big Brother house on the day she was pictured for first time since undergoing surgery.

Gary Goldsmith said Kate could be watching ITV’s Celebrity Big Brother from “behind a sofa” as the show kicked off on Monday.

Earlier in the day, Kate was pictured near Windsor Castle in the passenger seat of a car, according to TMZ.

The website showed a picture of the princess wearing dark sunglasses in the black Audi which was being driven by her mother, Carole Middleton.

It will be behind a sofa, I guess... It’ll be a nice one in a nice house, I can guarantee that

The photo – understood to have been taken by unauthorised paparazzi – is the first of Kate since she was pictured during a Christmas Day walk in Sandringham, Norfolk.

Asked by presenter AJ Odudu if Kate would be watching, 58-year-old Mr Goldsmith said: “If she is it will be behind a sofa, I guess… It’ll be a nice one in a nice house, I can guarantee that.”

In a pre-recorded interview which aired before he entered the house, Goldsmith said: “She is simply perfect.

“First time I met William, Catherine was cooking and William said, ‘Hi, do you want a cup of tea?’ Very normal.”

Towards the end of the programme, he told fellow housemate Fern Britton “I absolutely adore my family” after the TV presenter praised his decision to come on the show.

Speaking to The Sun before entering the house, Goldsmith described his niece as a “doting mum”.

“She’s beautiful on the outside, but more beautiful on the inside and really is a doting mum… so the way the monarchy is moving, it’s family-centric.”

He added he became “upset” with the Duke and Duchess of Sussex “because you don’t put a stick into that spoke and reinvent history”.

“Throwing your family under the bus just seemed inappropriate, especially what was happening with the Queen. I just thought it was totally unnecessary,” he added.

Kate was admitted to the London Clinic for a planned operation on January 16 and left the hospital on January 29 – almost two weeks later.

The 42-year-old returned to Adelaide Cottage in Windsor to be reunited with her three children, Kensington Palace said.

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

A week after she left hospital, the King announced he had been diagnosed with cancer and was receiving treatment.

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

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