The day Diana's birthday present to Charles backfired: As the king turns 76 we recall the princess's famous dance with Wayne Sleep in 1985 (as documented in The Crown) that left her husband unimpresse

Throughout Princess Diana 's 15-year marriage to Prince Charles there were dozens of instances where their clashing personalities were displayed for all to see.

But perhaps the most high-profile example was when the princess danced with ballet star Wayne Sleep as a surprise present for her husband's 37th birthday in 1985.

They performed a three-minute dance to Billy Joel 's 80s hit Uptown Girl to uproarious applause and eight curtain calls from the 2,500 VIP-only audience.

But despite the crowd's reaction, Charles did not stand. When the 25-year-old Diana left the stage and went to him enthused and desperately wanting his approval, he simply said 'well done, darling', and turned to talk to someone else.

No video footage exists of the now stuff-of-legend moment, and only a few pictures were taken by the in-house photographer who swore to never release them (although he did sell them in 1995 for around $250,000).

The performance became so iconic that it was since recreated in The Crown, where Charles was depicted as being furious at his wife's 'grotesque, mortifying display'.

Here MailOnline looks back at one of Diana's most beloved stunts and how it revealed to everyone she and Charles were very different people.

It was Diana's decision to do the secret performance with Sleep at the annual VIP show for Friends of Covent Garden at London 's Royal Opera House in December 1985.

Sleep at the time was a well-known British dancer who performed for some years with the Royal Ballet, but when he was approached by Diana he expressed scepticism that they could perform together due to his small 5ft 2in frame.

But they quickly became friends with Sleep saying they bonded over 'schoolboy humour' after Diana, who became a lifelong friend, called him a 'naughty boy' after he confessed to having a 'very late night' during their first early morning meeting.

Diana had studied classical ballet as a child but grew too tall at 5ft 10in to dance at the highest level but she still loved dancing throughout her life and was a supporter of the English National Ballet.

Years after the famous performance, Sleep wrote in The Guardian: 'She loved the freedom dancing gave her.'

The duo practised in various locations such as Sleep's personal studio in Kensington or in the drawing room of Kensington Palace to keep the Press in the dark about her movements.

The only people who were in on the secret plan were a detective and one of Diana's ladies-in-waiting Anne Beckwith-Smith - although neither knew what the actual dance was.

When it came time to perform, Sleep raised his hand on stage to give the signal and Diana slipped out of the royal box to change and join him.

As soon as the princess stepped out on the stage, the whole audience was in shock, and it took a moment for them to realise who it really was.

Sleep told Vulture in 2020: 'Everyone's mouths gaped open. There was an intake of breath like they couldn't believe it.'

One the performance itself he said, 'it wasn't a serious dance by any means' but it 'brought the house down with humor because the audience didn't know what was coming next'.

He said they did double pirouettes and a lift, and there was also a combination of jazz hip rolls.

It was very dynamic but 'nothing too difficult' with steps, lounges and transfers of weight. Sleep also said they had a few innuendos in the performance.

Although there was just the two of them, they ran the diagonals and really covered the whole stage.

Sleep later said 'she couldn't have danced it better' and that he was the nervous one, not Diana, out of fear he would drop the future Queen of England.

What's more, the dancer claims he even gave Diana a gentle push to bow to her husband - who was seated in the Royal Box.

Diana said to Sleep: 'No, I'm not bowing to him, he's my hubby. You won't get your OBE with those comments!'

She enjoyed the dance so much she wanted to perform an encore, but Sleep refused - saying his motto was to 'leave them wanting more'.

A few days after the performance, he got a letter from Diana which read: 'Now I understand the buzz you get from performing.'

But although the audience and press seemed to love Diana's performance, Charles strongly disapproved.

He had watched it completely oblivious to his wife's plan and in public confessed himself as 'absolutely amazed' by the display.

But according to Andrew Morton's famous book on Diana, Her True Story - In Her Own Words, in private he thought it was 'undignified' as she was 'too thin and too showy'.

He wrote: 'No matter how hard she tried or what she did, every time she struggled to express something of herself, he crushed her spirit. It wore her down.'

Diana's private dance tutor Anne Allan wrote in her new memoir: 'After repeated curtain calls, an elated Diana left the stage and enthused, "Beats the wedding!"

'She made her way to Charles, and as she stood before him, I could sense she desperately wanted his approval.

'He said, "Well done, darling", and turned to talk to someone else.'

Meanwhile royal expert Richard Kay claimed the 'Uptown Girl' routine was a 'present that backfired' on Diana.

He said: 'She did it as a tribute to Charles. Charles wasn't terribly impressed.

'He thought she was showing off. In fact, it was incredibly courageous of her to go on stage at the home of English ballet at Covent Garden and to do a routine with the great Wayne Sleep.'

According to royal biographer Tina Brown, Charles's reaction was interpreted, as 'frigid disapproval of Diana's lapse in royal etiquette'.

The iconic dance was also documented in the fourth season of The Crown in 2020, where Jay Webb (playing Sleep) and Emma Corrin (playing Diana) re-created the moment.

During the scene, Charles appears sullen and deeply focused on the music. But as soon as Diana makes her surprise appearance on stage, Charles tenses.

Afterwards, he becomes cold, asking his wife 'What were you thinking?' and calling the surprise a 'grotesque, mortifying display'.

Reflecting on the night of the performance itself, Wayne said it was drastically different to how it was portrayed in the TV show.

He said The Crown made it 'so shoulder-y' when in 'reality it was a little more elegant'.

But despite the fallout from the performance, Anne Allan said in the controversial documentary Diana: In Her Own Words how dancing helped Diana cope with the stress of her turbulent marriage to Charles.

She said: 'When I first met her you could see that there was a huge shyness. But over time as we went through our dance class realised just how much dance meant to her.

'She had dance in her soul. I realised the pure enjoyment that it gave her. She loved the freeness of being able to move and dance. She loved it. I could see it helped to alleviate her emotional life. That was hard for her at that time.'

Although it has been almost 39 years since the Uptown Girl dance, the moment has lived on in the minds of the British public as an iconic Diana moment.

As Charles, now King, looks back on all the birthday presents he received in his 76 years, he will no doubt remember the dance, and be glad there are a lot fewer surprises these days.