New royal favourite Harriet Sperling joked with the King on the hottest day of the year so far as she joined the family at Royal Ascot for the second time this week.
But Peter Phillips‘ NHS nurse girlfriend of more than a year kept her cool, despite Britain seeing highs of 32.2C at Kew, under an hour away, yesterday.
Even King Charles was seen adjusting his tie in the tropical conditions as other racegoers cooled down with magnums of champagne and old-fashioned fans.
And the going was stifling for the horses, who were doused in buckets of water as forecasters warned of a four-day heatwave set to see Britain turn hotter than Hawaii – with 34C (93F) expected in the South and East this weekend.
Ms Sperling – who was honoured to join the monarch’s carriage procession on Ascot’s opening day – shone in a £725 ‘Sienna’ lemon yellow dress from society favourite Beulah and a matching hat to keep the sun off.
And all eyes were on her as she chatted easily with His Majesty, who looked delighted to see his nephew’s girlfriend again.
It will add fuel to rumours that an engagement may be on the cards – not least because Peter and Harriet were seen holding hands and kissing in the Royal Box.
Paediatric specialist Harriet, 45, who has a daughter by a previous relationship, apparently met Princess Anne’s son at a sporting event attended by both their children.

Scorcher in the sun! The royals, led by King Charles and Queen Camilla, faced temperatures of 32C at Royal Ascot

All eyes were on Harriet Sperling as she chatted easily with His Majesty, who looked delighted to see his nephew’s girlfriend again
She lives in Gloucestershire, as does Peter, 47, who has two daughters by Canadian ex-wife Autumn.
There was certainly a family feel to yesterday’s racing, with the King inviting the Duke and Duchess of Edinburgh – who were celebrating their 26th wedding anniversary – to join him in the royal carriage procession down from Windsor Castle, along with his sister, Princess Anne, her husband Vice-Admiral Sir Tim Laurence, niece Princess Beatrice and her husband, Edo Mapelli Mozzi, as well his other niece Zara Tindall and her husband, Mike.
Queen Camilla looked coolly elegant in a silvery blue coat dress by Anna Valentine and matching hat by Philip Treacy, along with the Jardine Star diamond brooch.
The Berkshire racecourse has been enjoying record figures this week, and the King’s other guests in his carriage – the Marquess and Marchioness of Salisbury – were so impressed at the sight of the huge crowds, that the latter pulled her phone from her bag and started filming them as their landau thundered down the course to cheers.
It was Ladies Day at the meet, which attracted a host of celebrities and punters dressed to the nines, including former model Jerry Hall, who attended with her son Gabriel Jagger and daughter-in-law Anouk Winzenried.
But as the mercury soared to temperatures in excess of 32C –almost 90F – racegoers clad in their finery, including full morning suits for the men, began dropping like flies.
At least one person was taken to hospital and more than 40 treated for heat-related illness.
As the Hawaii-topping highs of 34C were predicted for tomorrow, in contrast, Honolulu, capital of the US Pacific Island state, is only forecast to reach 29C (84F), while Barbados should hit 32C (89F).

Even King Charles was seen adjusting his tie in the tropical conditions

Ha-Bea-ness: Princess Beatrice watched on excitedly from the royal box

Racegoers cooled down with huge magnums of champagne on day three of the races

It appeared everyone was feeling the heat – even the horses, who were cooled down with buckets of water

Family affair: Jerry Hall with her daughter-in-law Anouk Winzenried

Old-school: The accessory of choice on the UK’s hottest day so far was the traditional fan
The last time Britain reached 34C in June was almost six years ago on June 29, 2019, at Northolt and Heathrow. The record for the month is 35.6C (96.1F) on June 29, 1957, at Camden Square, central London.
As The UK Health Security Agency issued a four-day amber heat health alert from noon yesterday until 9am on Monday, even Newcastle-upon-Tyne is forecast to hit 31C (87.8F) tomorrow.
The agency warns ‘significant impacts are likely’ across health and social care services because of high temperatures, including a rise in deaths – particularly among those aged 65 and over.
An official heatwave is logged when areas reach a certain temperature for three consecutive days, with thresholds varying from 25-28C (77-82F) in different parts.
Temperatures are set to fall back to the mid-20s by the start of next week.