“I don’t even need to work; I really do it out of passion for well-being,” starts Valérie Orsoni. The San Francisco-based celebrity trainer has made a name for herself training — although she would never confirm their identities — A-list Hollywood stars, rumored to include the likes of Jennifer Aniston, Demi Moore, Jennifer Lopez and Kim Kardashian.

“Unless they kindly agree to it, I would never reveal the name of a client,” explains the trainer. It’s through Jason Moore, Paris Hilton’s former manager, that Orsoni meets most of them. Usually, she doesn’t work for them for a long time. “Stardom makes it really hard to do anything long-term,” she explains. “They are always torn between their manager, agent, guru du jour, friends or the latest fad in their endless search for perfection.”

Orsoni developed her method after putting on weight following her parents’ divorce. Between the ages of 15 and 18, she tried all the diets she could find: 42 in total, according to her. To find one that actually worked, she created a mash-up of all of them.

Her method is not about starving yourself, cutting out entire food groups or extreme exercise routines. And yet, her clients aren’t always on board. “Some of them are really motivated but easily crack for food,” she says. “While some of them always find excuses, and I hate excuses. Especially when they pretend to be tired when they were up all night partying under the eyes of the paparazzi.”

It was dealing with the excuses that gave the fitness expert new ideas about keeping them motivated, which she shares in her new book, “Le BootCamp Diet,” out today. “One of them told me that she couldn’t be bothered putting on her gym clothes in the morning. I told her to sleep in them!”

On the other hand, you also have the “well-behaved” who wake up at 4:30 a.m. to work out and wouldn’t dare to put French fries in their mouth. There is also a secret motivator no one really likes to admit: the rivalry with a competitor, either for a role or for a partner, which can definitely help them get out of bed. “They want to be skinnier than their ex-boyfriend’s new flame,” the coach laughs.

To help her famous clients tackle the extra pounds before shooting a film or walking the red carpet, Orsoni makes them go on a detox, eating “mostly plants and seafood — not fried, of course. It’s a mix of low-GI [glycemic index] and alkalizing food like papaya, pineapple, berries, nectarines and sprouted seeds and nuts, which will also give them glowing skin.” She also sometimes prescribes an infrared sauna session every day, to improve circulation.

Another tip from the coach: “One hour before putting on the dress and makeup, some push-ups will really add definition.”

In the long run, however, she wouldn’t recommend cutting any food. “My program is based on no guilt. I think depriving yourself just makes you more likely to compensate afterwards and put the weight back on.”

We’d all happily stick to that rule.

How to make sure lost weight is gone for good

• Before breakfast, drink water with lemon juice at room temperature
• A few minutes later, drink a homemade sobacha (buckwheat tea)
• Walk for 30 minutes before eating breakfast (this is also beneficial before lunch and dinner)
• Stick to the “no-excuse rule”: Whatever the obstacle standing between you and your workout, there is always a solution
• Reduce your dairy intake as much as possible
• Learn how to breathe properly to reduce stress
• When you go to bed, turn off all electronic devices (yes, even your phone) and put them in another room to avoid any disturbance during the night