I know what the super rich REALLY do on yachts – from models who ruin furniture by dancing on it in stilettos to the famous actress who just couldn’t control herself…

Was there any way to stop the ship from rolling so much in the rough seas? And was it possible to reduce the three-week voyage to just one?

Every request is met with the same patient, unfazed smile. “Of course, ma’am. Allow me to take control of my time machine and speed dial Neptune,” words that, unfortunately, I could only say in my head.

This made his demands that a certain type of caviar be flown in for lunch and that a party with champagne and the presence of world superstars be organised at the drop of a hat seem entirely reasonable.

Welcome to the start of the Mediterranean summer superyacht season, the annual takeover by the rich and famous, whose extravagant, outlandish and absolutely indulgent requests must be indulged by the crew at their service.

As the summer superyacht elite (including regulars Beyoncé and Jay-Z, Catherine Zeta-Jones and Michael Douglas, the Clooneys and Leonardo DiCaprio) descend on continental Europe and prepare to bed down aboard luxury decks, crew members like me are prepared to indulge their every whim.

Now 37, I have spent the last decade working as a stewardess on luxury yachts around the world and have appeared on the television series Below Deck Sailing Yacht. As you can imagine, this life has given me more than just a fleeting glimpse into the world of celebrity aboard some of the most elegant floating gin palaces.

The confidentiality agreements that all crew members are required to sign to protect our guests’ identities, as well as their secrets, mean that I will be kept silent forever. But what I can reveal is that among the celebrities I have met are A-list actors, world sports stars and millionaire models, as well as countless high net worth individuals.

There have been many times when I have been drawn to him. Once, a very famous actress was enjoying a good wine on board and her agent tried to stop her from serving. But what a guest wants, he gets.

In a world where colossal egos and huge wallets collide, a typical day on a superyacht is like managing the most opulent five-star hotel.

I handle the mid-shift, overseeing everything from meals to cleaning the deluxe cabins, organizing guest itineraries, and generally being your concierge – all at the click of a finger. Need to see a doctor? I’ll have one on board in no time. Want a table for lunch in a fancy but crowded restaurant? I’ll make it happen. How about a helicopter to meet friends for dinner? Consider it done.

Most of my time has been spent working on privately owned boats and in the second (third, fourth, fifth…) homes of their owners. For three years I travelled the world with a couple and their young son who had built an amazing 46-metre sailboat with four guest cabins and a library.

Even grander was the 56-metre motor boat which cost £13m and cost around £1m a year to maintain. This was my ‘office’ for a year, based in Monaco during the winter and Greece during the summer.

Guests often get outrageous requests and anything goes. I have been to French Polynesia several times and have had owners or guests insist that we fly food in from the States because there simply aren’t enough provisions on these small, remote islands to satisfy their tastes.

In Europe, of course, it’s pretty easy to get anything a guest’s heart desires. A common request is for companions to join guests on board for some private, ahem, fun. Whether or not these demands are met is up to the captain and crew. Some say no, others simply do as they’re told, make the right decisions on land and then turn a blind eye.

The crew is an incestuous world where everyone knows everyone else and as the various yachts dock next to each other at exclusive resorts across Europe, we swap stories.

A yachting enthusiast friend recently told a gossip about some famous models. They had danced around in their stilettos, making countless holes and dents in the yacht’s seats, costing them millions. When they were politely asked to take off their shoes, they refused because, they said, it would ruin their overall image.

A hot topic is what the other crew members get up to. Although sex with guests is strictly forbidden, it is not uncommon for the crew to have discreet affairs with the adult sons and daughters of guests and yacht owners during their family vacations.

Our season traditionally kicks off with the Cannes Film Festival in May, which sees the first wave of famous faces, either on their own yachts, on chartered boats or just partying on board by invitation. The owner of a yacht I worked on lent the boat to his cousin during the Cannes festival and they partied non-stop with world stars and film directors, drinking more bottles of Cristal champagne than I have ever seen in my life.

At the beginning of summer, the atmosphere changes dramatically. Sailing is a competitive field, and boats, owners and guests vie for supremacy on the waves. Chefs take part in culinary competitions before the season, with the aim of winning prizes that will increase a boat’s prestige.

Some have a photographer on speed dial to ensure that guests who want to capture their luxury stay can do so with brilliant, artistically posed photos of their superyacht experience.

Fortunately, in my experience, the richer a person is, the nicer they are. I work mainly with multi-millionaires and billionaires, most of whom are classy people, treat the crew well and reward hard work. My biggest tip was £9,000.

Then there was the family who gifted me and the rest of the team a stay at their chalet in Aspen (twice), flying us there on a private jet.

Another guest paid £35,000 for nine of us to party at the exclusive Nikki Beach in St Tropez. But that’s a drop in the ocean when you’re paying more than £200,000 a week to stay on one of Europe’s most luxurious yachts.

The loudest and worst behaved yachts tend to be those with young, wealthy guests for whom the life of luxury is nothing new. They use all the jet skis and demand that the crew prepare every cocktail on the drinks menu.

For some celebrities, the same yacht every summer is enough. For them, luxury is the familiarity of a boat and crew, enjoying water sports and making memories with family. But for every yacht peacefully cruising the Mediterranean, there’s another one bouncing around with guests whose sights are set on luxury and letting others know about it.

And once the sun sets on Europe’s summer superyacht season in September, wealthy yacht owners simply board the glittering Geneva palaces further afield, in search of winter sunshine, with none of the glamour, glitz or gossip.

• As told to Sadie Nicholas