Pippa Middleton has been "stepping up her workouts" in preparation for her wedding.

Pippa Middleton

Pippa Middleton

The 33-year-old sister of Catherine, Duchess of Cambridge, is set to tie the knot with her fiancé and hedge fund manager James Matthews next month, and has reportedly been exercising "four or five times a week" in order to make sure she's in shape for the big day.

A source explained: "Pippa has been stepping up her workouts getting ready for her wedding. She's been working out about four or five times a week.

"She's been working with a personal trainer at a gym near her home in Chelsea and also has been doing Pilates. She looks and feels great - she's never looked better."

The source also said that the exercise regime isn't out of the ordinary for the brunette beauty - whose sister is married to Prince William - as she's "always been active and athletic", and adds she's also been getting facials and hair treatments to prepare her for her walk down the aisle.

The insider added to 'Entertainment Tonight': "Pippa has always been active and athletic, but she's very lean and muscular right now. She's been detoxing with a healthy diet and also has been getting regular facials. She's also been visiting her favourite salon, Richard Ward, for hair treatments."

Meanwhile, it was recently revealed that Pippa and James - who is the brother of 'Made In Chelsea' star Spencer Matthews - will have a "no expense spared" wedding.

A source said: "It will be blingtastic. The best champagne, Krug or Bollinger, and a specially devised champagne cocktail.

"Pippa and James have a penchant for Blanc de Noir Tillington 2009 from Nyetimber at £75 a bottle - and wonderful food. No expense will be spared. This isn't a bangers-and-mash, sitting-on-hay-bales affair. Pippa is hardly a floaty bohemian type."

The couple will be joined by their guests at St Mark's Church in Englefield on May 20 for the service whilst 350 or so will be expected to attend the reception, which is thought to be taking place in the grounds of her parents Carole and Michael Middleton's family home in Bucklebury, Berkshire.