Pippa Middleton is a "military-fitness obsessive".
The 30-year-old beauty, who is the sister of Britain's Duchess Catherine, admits she's a fan of the gruelling classes in her latest column for Waitrose Magazine.
The February edition features the stunning brunette cooking French puddings for Valentine's Day with Michelin-starred chef Eric Chavot.
She writes: "Early morning - a tad too early, even for a military-fitness obsessive like me - and I'm in an underground kitchen in London's Mayfair sitting next to a gregarious Frenchman in shorts."
Pippa is known to keep herself toned and healthy and often attends classes with pilates guru Margot Campbell.
She has also competed in sporting events and finished the 90km Vasaloppet cross-country ski race in 2013.
Military fitness classes are known for being tough and not for the faint-hearted, with participants often having to get up before sunrise to train in local parks.
The British Military Fitness website reads: "With the encouragement of your fitness instructor you'll train in pairs, in groups and teams, climbing over, crawling under and running around each other from the first to the last minute."
Meanwhile, Pippa has sparked rumours she's split from her boyfriend, Nico Jackson, who she has been dating for over a year, after she attended a wedding without him this month.
She arrived at St Paul's Church in Knightsbridge, London, on February 8 for the nuptials of Arrabella Musgrave and George Galliers-Pratt.
Arrabella - who is the daughter of Major Nicholas Musgrave - dated Prince William in 1999 before he went on to meet Catherine at the University of St Andrews in Scotland.
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