Princess Eugenie is at her best shape ahead of her royal wedding.

The next royal bride is prepping for her big day. A number of royal fans notice that Princess Eugenie appears slimmer just months ahead of her nuptials. According to Francesca Specter, a lifestyle reporter for Express, her choice of drinks has contributed to her figure.

Based on Princess Eugenie's previous interview with Harper's Bazaar, her favorite drinks include green tea, coffee, Diet Coke and fizzy water. For alcoholic drinks, she prefers vodka and soda.

According to Specter, these drinks are favorites among dieters because they contain little to no calories. Personal trainer Jess Tonking commended Princess Eugenie's weight loss success.

"Princess Eugenie has a gorgeous shape with all the right curves but it does appear more recently she may have shed some body fat in prep for her wedding," Tonking said. "If she has been following a weight training programme it's hard to determine how much weight she has lost due to muscle gain."

"I believe she may have lost three per cent body fat (four pounds of fat loss) in the 6 weeks since the Royal wedding," the fitness expert continued. "Half a percent a week is a healthy and manageable amount of fat loss which can be maintained. It may not sound like a lot but this is a great achievement, everyone should focus more on fat loss percentage rather than weight."

On the other hand, Daria Kantor, the founder and CEO of TruBe also noticed Princess Eugenie's slimmer frame. According to her, the next royal bride seemed to do it the right way because of her glowing skin.

"Princess Eugenie seems to have lost weight in a healthy fashion. Her skin is glowing, she looks fitter and more toned – she's clearly put the work in," Kantor said.

According to Princess Eugenie, she wakes up early to exercise. She also shared the activities she does to keep in shape.

"I get up around 6:45 to start exercising by 7," Princess Eugenie said. "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. It's much better, as I can't run for a long time."

Princess Eugenie and Jack Brooksbank are tying the knot on Oct. 12 at St. George's Chapel at Windsor Castle.