Zara Tindall was a ray of sunshine today as she joined the King and Queen at Royal Ascot for Ladies Day.The daughter of Princess Anne, 45, put on a fashionable display in a chic belted yellow dress from Rebecca Vallance, featuring statement sleeves and pocket detailing.She teamed the glamorous frock with a matching Anya Hindmarch clutch bag and hat, from Sarah Cant Millinery, and added more height to her frame with a pair of metallic gold heels from Emmy London.Keeping the sun from her eyes with some stylish sunglasses, the late Queen's granddaughter, who is 22nd in the line of succession to the British throne, completed her look with dazzling drop earrings.So far, Zara has attended all three days of Ascot, the jewel in the crown of the UK racing calendar.She was joined in the parade ring today by the King and Queen, Princess Anne, the Duke and Duchess of Edinburgh as well as Hollywood actor Stanley Tucci.The Hunger Games star, 65, who is a regular at royal events and dinner parties, joined Their Majesties during the royal carriage procession at the Berkshire racecourse.He was joined by his wife Felicity Blunt, 45, who is the sister of Tucci's The Devil Wears Prada co-star, Oscar nominee Emily Blunt. Zara Tindall was a ray of sunshine today as she joined the King and Queen at Royal Ascot for Ladies DayAnother famous face making their debut in the Royal Family's Ascot procession was the Earl of Snowdon's long-term girlfriend, Isabelle de La Bruyere, as the pair had the honour of riding alongside King Charles and Queen Camilla. Smiling at the crowds, Princess Margaret's son David Armstrong-Jones, 64, has been dating the French art dealer since 2022, two years after he split from his wife Serena Stanhope after 27 years of marriage. While the loved-up royal couple attended Ascot together last year, today was the first time Isabella has joined the royal carriage procession – as she cut a striking figure in a white dress with a black belt. Senior royals joined thousands of stylish racegoers who put their best fashion foot forward as Ladies Day got underway. However, the warm weather meant sleeveless dresses and airy skirts were popular sartorial choices – as the UK braces for the start of a six-day heatwave with temperatures expected to rise to 27C this afternoon. A static area of high pressure building across mainland Europe – known as a 'heat dome' – is resulting in increasingly warm and humid air for southern England.London, the East, South East and South West regions were placed under the amber alert, while the Midlands faces a yellow warning. There are no alerts for the North.These warnings run from midday today until next Tuesday at 8pm – although the Met Office forecast currently suggests the heatwave could last until at least Wednesday.The daughter of Princess Anne, 45, put on a fashionable display in a chic belted yellow dress from Rebecca Vallance, featuring statement sleeves and pocket detailing Zara teamed the glamorous frock with a matching Anya Hindmarch clutch bag and hat, from Sarah Cant Millinery, and added more height to her frame with a pair of metallic gold heels from Emmy London Keeping the sun from her eyes with some stylish sunglasses, the late Queen's granddaughter, who is 22nd in the line of succession to the British throne, completed her look with dazzling drop earrings So far, Zara has attended all three days of Ascot, the jewel in the crown of the UK racing calendar Zara was joined in the parade ring today by the King and Queen, Princess Anne, the Duke and Duchess of Edinburgh as well as Hollywood actor Stanley TucciThe amber alert states that the areas covered are likely to see 'a rise in deaths, particularly among those aged 65 and over or with health conditions', while 'significant impacts are likely across health and social care services' due to the heat.At Royal Ascot, temperatures reached around 22C this morning and are expected to reach 27C by the afternoon.The annual festival started on Tuesday with the Queen Anne Stakes and will run until Saturday. Yesterday, Zara sported a satin navy dress with a floral print on day two of the occasion.