I know what the super-rich REALLY get up to on yachts: From models ruining the furniture by dancing on it in stilettos to the famous actress who simply couldn't control herself...

Was there any way of stopping the boat from rocking so much in the choppy sea? And that three-week voyage, could it possibly be cut to just one?

Each request is met with the same, patient, unflappable smile. ‘Certainly, Madam. Let me commandeer my time machine and get Neptune on speed dial,’ words, sadly, I could only say in my head.

It made their demands for a certain type of caviar to be flown in for lunch on a whim and a champagne-steeped party, complete with global superstars, to be mustered at the drop of a hat, seem entirely reasonable.

British supermodel Naomi Campbell and Mexican actress Eiza Gonzalez sun themselves on a luxury superyacht in Ibiza

British supermodel Naomi Campbell and Mexican actress Eiza Gonzalez sun themselves on a luxury superyacht in Ibiza

Daisy Kelliher starred on seasons 2, 3 and 4 of Below Deck Sailing Yacht, which details the lives of crew aboard a vessel

Daisy Kelliher starred on seasons 2, 3 and 4 of Below Deck Sailing Yacht, which details the lives of crew aboard a vessel

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

As the summer superyacht elite — regulars include Beyonce and Jay-Z, Catherine Zeta-Jones and Michael Douglas, the Clooneys and Leonardo DiCaprio — descend on continental Europe and prepare to drape themselves aboard luxury decks, crew members like me are poised to pander to their every whim.

Now 37, I’ve spent the past decade working as chief stewardess on luxury yachts around the world, and have starred on the TV series Below Deck Sailing Yacht. As you can imagine, this life has gifted me more than a passing glimpse into the world of celebrity aboard some of the sleekest floating gin palaces.

The non-disclosure agreements all crew members are obliged to sign to protect our guests’ identities, as well as their secrets, mean that I am forever hushed. But what I can reveal is that the celebrities I’ve encountered have included A-list actors, global sports stars and million-dollar models, as well as countless high net worth individuals.

There have been many ‘pinch me’ moments; once a very famous actress was enjoying rather a lot of fine wine on board and her agent tried to get me to stop serving her. But what a guest wants, a guest gets.

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

I manage the middle shift, overseeing everything from meals to cleaning the luxury cabins, organising the guest itineraries and generally being their concierge — all done 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 at a swanky but fully booked restaurant? I’ll make it happen. How about a helicopter to meet friends for dinner? Consider it done.

Mostly I’ve worked on boats that are privately owned and the owners’ second (third, fourth, fifth...) home. For three years I travelled the world with one couple, and their young son, who’d built an incredible, 46 metre sailing boat with four guest cabins and a library.

Grander still was the 56-metre motorboat worth £13million, which cost around £1million a year to run. That was my ‘office’ for a year, based in Monaco during the winter and Greece in the summer.

As the summer superyacht elite, including Beyonce and Jay-Z (pictured), descend on continental Europe and prepare to drape themselves aboard luxury decks, crew members are poised to pander to their every whim

As the summer superyacht elite, including Beyonce and Jay-Z (pictured), descend on continental Europe and prepare to drape themselves aboard luxury decks, crew members are poised to pander to their every whim

Actor Leonardo DiCaprio is an avid user of superyachts - often spending time on them with other celebrities and supermodels. Pictured in St Tropez last summer

Actor Leonardo DiCaprio is an avid user of superyachts - often spending time on them with other celebrities and supermodels. Pictured in St Tropez last summer

George Clooney looks out at the view from a yacht off the coast of the South of France. Pictured in 2000

George Clooney looks out at the view from a yacht off the coast of the South of France. Pictured in 2000

Wild requests from guests are the norm and literally anything goes. Several times I’ve been in French Polynesia and the owners or guests have insisted we hire a plane to bring food in from America because there simply aren’t the provisions on these small, remote islands to cater for their tastes.

In Europe, of course, it’s pretty easy to get your hands on anything that a guest’s heart desires. A common request is for escorts to join the guests on board for intimate, ahem, fun. Whether such demands are pandered to depends on the captain and crew. Some say no, others simply do as they’re told, make the right calls ashore and then turn a blind eye.

Crewing is an incestuous world where everyone knows everyone else, and as the various yachts moor up alongside one another in Europe’s exclusive resorts we swap stories.

A recent top bit of gossip from a yachtie friend involved some famous models. They’d danced in their stiletto heels, punching countless holes and dents in the yacht’s seating, which cost millions. When politely asked to take their shoes off, they refused because, they said, it would ruin their overall look.

Kim Kardashian posts a picture of herself enjoying the sunset aboard a yacht to Instagram earlier this month

Kim Kardashian posts a picture of herself enjoying the sunset aboard a yacht to Instagram earlier this month

One hot topic is what fellow crew members get up to. Though sex with guests is a complete no-no, it’s not uncommon for crew to have discreet flings with the grown-up sons and daughters of yacht guests and owners during their family holiday.

Our season traditionally starts with the Cannes Film Festival in May, which sees the first swell of famous faces either on their own yachts, boats they’ve chartered or simply partying on board by invitation. The owner of one yacht I worked on loaned the boat to his cousin for the duration of Cannes and they partied non-stop with global stars and film directors, downing more bottles of Cristal champagne than I’ve seen in my life.

There’s a real shift in mood at the start of summer. Yachting is a competitive scene and the boats, owners and guests vie for supremacy on the waves. Chefs enter culinary competitions ahead of the season, targeting awards that will add kudos to a boat’s profile.

Some have a photographer on speed dial to ensure guests who want to capture their luxury sojourn can do so with artfully posed, glossy photos of their superyacht experience.

Fortunately, my experience is that the richer the person, the nicer they are. I work mainly with multi-millionaires and billionaires, the majority of whom are classy, 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 crew a stay at their chalet in Aspen — twice — flying us there by private jet.

Another guest footed a £35,000 bill for nine of us to party at the exclusive Nikki Beach in St Tropez. But that’s a drop in the ocean when you’ve paid upwards of £200,000 a week to stay on one of the plushest yachts in Europe.

The rowdiest, and worst behaved, yachts tend to be those with rich, younger guests for whom a life of luxury is less of a novelty. They’ll use every jetski and demand the crew make every cocktail on the drinks menu.

For some celebs, only the same yacht every summer will do. Luxury for them is the familiarity of a boat and crew, enjoying watersports and making memories with family. But for every yacht gliding peacefully across the Med, there’s another bouncing with guests whose sights are trained on indulgence and letting everyone else know it.

And once the sun sets on the summer superyacht season in Europe come September, the wealthy yachties simply board glittering gin palaces farther afield, chasing winter sun — with no less glamour, glitz or gossip.

  • As told to Sadie Nicholas