Kate Middleton has long been heralded a fashion icon for her impeccable taste in British designers from Alexander McQueen to Jenny Packham.

But before the Princess of Wales, 43, received style training on how to dress like a senior royal, it seems she was still finding her feet when it came to fashion.

As revealed in a new book by royal expert and journalist Tom Quinn, Prince William, 42, once found one of his wife’s outfits to be ‘inappropriate’ and allegedly made a cruel jibe.

In an extract from Yes Ma’am: The Secret Life of Royal Servants seen by FEMAIL, one of William’s advisers said: ‘Before Kate realised that as a senior royal you have to dress carefully, having taken advice, she once bought an outfit that William considered inappropriate.

‘He told Kate she looked as if in order to dress she’d just run through a charity shop covered in superglue.

‘Everyone thought this was very funny, including, to her credit, Kate.’

But Quinn also suggested that the Princess of Wales is more than capable of getting her own back.

‘She enjoys ribbing him about his family,’ a passage in the new book reads. ‘She insists that, as he gets older, William increasingly looks like his great-great-great grandfather Edward VII’ – whose waist measured 48 inches shortly before his coronation.

Born in 1841, Edward was the second child and eldest son of Queen Victoria and Prince Albert.

He succeeded to the throne in 1901 following Victoria’s death and was seen an ‘immensely popular and affable sovereign’, according to Britannica.

But a lifetime of smoking and indulgent eating meant that the former King was unhealthy, balding and overweight earning him the nickname ‘Tum Tum’ – a delightful comparison for Kate to make.

The Princess of Wales is also said to get a kick out of ‘teasing’ Prince William ‘about the fact that his stepmother Camilla is descended from Edward VII’s favourite mistress’.

A sharp sense of humour seems to be central to William and Kate’s relationship – having been spotted sharing a joke together countless times over the years.

Indeed when the couple revealed their engagement to the world on November 16, 2010, William could not help but sweetly tease his wife-to-be.

Asked by journalist Tom Bradby if it was true that Kate had posters of William on her wall, the Prince said: ‘It wasn’t just one, it was like 10, 20 [posters].’

To which Kate replied: ‘He wishes. No, I had the Levi’s guy on my bedroom wall, not a picture of William. Sorry.’

Royal fans were glad to see the couple’s sense of humour persevere throughout the years.

While visiting a military base in Cyprus in December 2018, William spotted some bright yellow sofas in the relaxing video room and teased the servicemen by saying: ‘Keep the pizza off the sofas!’

His witty wife quipped back ‘You’re a nightmare with that!’

During a subsequent trip to Scotland in 2021, Kate attempted to DJ at the Scottish Violence Reduction Centre in East Lothian while William quipped that her tune is ‘hurting my ears’ and sounds like a cat’.

‘It might catch on in about 100 years time,’ he added.

In October 2023, when BBC Radio One presenter Vick Hope asked the Prince and Princess of Wales which emoji they use most frequently, William said: ‘Is this a clean thing? Is it a family one?’

Meanwhile Kate joked: ‘It depends what group, if it’s the family WhatsApp group.’

William continued: ‘I’ve been told not to pick the aubergine, so I’ve got to pick something else.’

He added: ‘It would have been the aubergine, but I’m saying now because I’ve got to be a little grown up that it’s the one with the eyes [that] go up and down, and the mouth.’

Revealing her emojis of choice, Kate said: ‘It’s got to be the heart, with then the crying emoji, the sort of like hysterical laughing when things go wrong.’

Show hosts Jordan North and Vick Hope appeared both shocked and delighted at William’s response.

Jordan said: ‘He said the aubergine emoji, this is brilliant.’

Meanwhile Vick is reported as saying: ‘He knows. He’s got a dirty mind.’

• Yes, Ma’am – The Secret Life of Royal Servants by Tom Quinn (published by Biteback, £20) is available for pre-order.