Zara and Mike Tindall have given the changes to Cheltenham's dress code their royal approval.
The couple praised the 'inclusive' nature of The Jockey Club's decision, made just weeks before the 2023 Festival.
Fans at the four-day meeting, the pinnacle of jump racing, will no longer be bound by rules telling them to wear a formal outfit. Instead racegoers, who numbered 280,627 overall at last year's event, have been advised to go 'dressed to feel your best'.
Items of clothing permitted include trainers and jogging bottoms – although football kit and offensive attire is not.
The Tindalls, interviewed for William Hill’s horse racing show, The Inside Track, had their say on the issue which has divided followers of the sport.
Zara, who has been on Cheltenham Racecourse's committee since 2019, said: "They’re just trying to be more inclusive. And it’s a different time of year as well.
"You want to stay warm. It’s an easier time of year to stay more casual and still feel part of everything as well. "
Mike, who owned top racehorse Monbeg Dude who placed in the Grand National, added that many racegoers will still dress up for their day at Cheltenham, which begins on March 14.
The new clothing guidance also covers the National track, Aintree, one of 15 venues in the group.
"I quite like the bit where a lot of people want to get dressed up and go to the races. If they want to, they can do that," Mike said.
"It's more of a statement to say that there is always – whatever you want to wear."
Past dress code rules required men to wear suit jackets in certain enclosures at all times, with jeans and shorts generally not allowed.
A statement on the Jockey Club’s website said: "We’re all unique, and no more so than in our sense of style and comfort. For some, wearing a nice sweatshirt, pair of jeans and clean trainers is what makes them feel confident and at ease."
Zara, who has been going to the Cheltenham Festival for around 25 years, said one of her favourite races is the Queen Mother Champion Chase
That is because of her memories of going to the big meeting with her great grandmother. The two-mile championship was given its title in 1980 to recognise the Queen Mother's support to jump racing.
Zara suggested that many racegoers enjoy beginner's luck when betting at the races.
"When I've taken people racing the people who have done the best at putting a bet on have got no idea!" she said.
"They turn up and (say) my granny's dog is called so and so. They pick links like that and they win all day long."
