Eugenie's new look comes after it was revealed the bride was sticking to an intense diet regime in the lead up to her big day at St George's Chapel in Windsor.
According to reports, the princess has turned to the same London-based nutritionist Prince Harry used to trim up ahead of his wedding to American actress Meghan Markle.
The Mail on Sunday reports that Princess Eugenie has recruited Gabriela Peacock to help her get in shape.
According to the model-turned-nutritionist’s website, Gabriela works at the prestigious Grace Belgravia clinic, having been headhunted by the Queen’s GP Dr Tim Evans in 2013.
The expert now creates bespoke nutritional packages for London’s fashion and celebrity elite – which apparently included Prince Harry who lost three kilos ahead of his wedding earlier this year and his now wife, the Duchess of Sussex.
Ms Peacock’s range of diet powders include Slim Me, Clean Me, Energise Me, Calm Me and Protein Me – all of which cost £100 for a month’s supply.
The best seller, Slim Me, is a gel sachet with ingredients including the dietary fibre glucomannen which swells in the stomach and suppresses hunger.
While the Duke and Duchess of Sussex apparently embraced green detox juice made from apples, lemon, ginger and spinach during their health kick, Eugenie has previously opened up about how she gets up at the crack of dawn to stay in shape – before hitting Grace Belgravia for a workout.
"I go to the park from 7 to 8. I do circuits, which I love because they're quick: burpees, squat jumps, lunges, the whole lot," she told Harper’s Bazaar back in 2016.
"It's much better, as I can't run for a long time. Or I go with my best friend to this amazing, women-only gym called Grace Belgravia."
"For lunch, I walk over to the Detox Kitchen, which is right across Regent Street in Kingly Court. They do the best food, all healthy," she added.
"There's often a queue outside. I try to not eat at my desk because it's good to go outside, especially in the summer, and it's always fun to explore Soho. During the day I drink everything from green tea to coffee, Diet Coke to fizzy water."