Beckham, his wife Victoria and their four children are reported to have headed to the luxury Amanjena Resort near Marrakesh, where the couple renewed their marriage vows in 2004, and a host of celebrities will jet in to get the party in full swing.
Victoria has been discussing the party on Twitter, writing “What to wear in Marrakesh? Vintage Yves Saint Laurent #DB40 x vb.” and posting a picture of a dress.
The guest-list is said to feature high-profile friends of the Beckhams, including Hollywood actor Tom Cruise, film director Guy Ritchie, chef Gordon Ramsay and football agent Dave Gardner, the partner of glamourous actress Liv Tyler.
It is exactly the kind of high-profile gathering that Beckham has been attracted to since he burst onto the English football scene in the 1990s.
The global interest in the event provides further evidence that ‘Brand Beckham’ remains as strong as ever two years after his tearful retirement following his final appearance for Paris Saint Germain.
Beckham has nine major sponsorship deals with some of the biggest brands in the world like Adidas, H&M and Jaguar and marketing consultant Nigel Currie sees no limits to his earning power.
“If you were looking for someone to represent you, he would be first on the list. He has got a unique pulling power. He appeals to everyone,” he said.
“Retired footballers used to open pubs. But he has broken so many barriers.
“He has taken himself into areas which go well beyond football, whether it be fashion, or music.
“He has a celebrity wife and now almost a celebrity family, he has unbelievable ability to grasp the PR side of things. His earnings will just go up.”
The Beckhams are the 410th richest people in the UK, according to the Sunday Times Rich List, worth £240 million ($360 million).
That vast wealth is a far cry from the days when Beckham used to earn £10 a shift collecting glasses at the Walthamstow dog track in London.
He has become a master at exploiting his commercial appeal and as soon as he signed for the Los Angeles Galaxy in 2007, he had the first stage of his retirement sorted after a clause was inserted into his contract that would allow him to create his own Major League Soccer franchise.
Beckham has been working hard to put the finishing touches to that franchise in Miami, with financial backers and stadium location to be finalised in the coming months.
While Beckham’s post-football career trajectory remains in the ascendant, he will always be most fondly remembered for his exploits for United and England.
Beckham fulfilled a dream by making his name with the club he and his father both supported, wining six Premier League titles and the 1999 Champions League.
He also made 115 appearances for England, captaining his country 59 times, won the Spanish title with Real Madrid and the MLS Cup twice with the Galaxy.
Yet despite all those achievements, Beckham’s 40th birthday is unlikely to prompt a more leisurely lifestyle for a man who plans to turn his Miami franchise into an MLS superpower while perhaps watching his son Brooklyn follow in his footsteps on the pitch.