Hip-hop star, entrepreneur worth more than $450 million (Dh1.6bn)and husband to Beyoncé - you might think the rapper Jay-Z would be tempted to sit back and enjoy his success for a while.
Yet there he is, branching out in the restaurant business by opening a new London restaurant and club with the British footballer Ashley Cole. Called 40/40, the restaurant will be the first European outpost of a project the mogul has already rolled out in the US.
The owners plan to match the place's high-end swagger with a social conscience, training the long-term unemployed to be staff members and donating a proportion of its profits to charity. Having such famous figureheads for the project - Cole's record as a serial love cheat notwithstanding - has already done 40/40 London many favours, giving it a level of pre-publicity most restaurants can only dream of. At the same time, having celebrities at the helm is no guarantee of a restaurant's success.
This week Eva Longoria's Las Vegas nightclub Eve closed after filing for bankruptcy, reportedly due to massive debt, and although the attached Beso Steakhouse continues, creditors are seeking a trusteeship. Likewise Britney Spears, Jennifer Lopez and the 1990s' supermodels have all been behind restaurants that bombed - even the Hard Rock Café celebrity links didn't stop it closing in Dubai (although Hard Rock Hotels are due to open in Abu Dhabi and Dubai in 2013).
So why do some celebrity restaurants fail and others thrive? I talked to the London-based industry expert Mark Harris, of Harris Restaurant Consultants, to find out why.
"The key is not to be too hands-on," says Harris. "Celebrities should leave the everyday running and planning to people who really know what they're doing. Everyone thinks running a restaurant is terribly glamorous, and it certainly looks that way until you actually get involved. When things go wrong - as they often do - you can quickly get to the point at which you hate the business."
This might well be true of Lopez's restaurant Madres in Pasadena, California. Dishing up Latin classics, Madres survived for six years - a healthy run, in celebrity restaurant terms - before it closed abruptly in 2008. With no major disasters on record and no public announcements when it shut for good, it seems that Lopez simply got bored with the constant vigilance the project required.
Unsurprisingly, serving the right food is also essential.
"It's important to give the customer what they want," says Harris, "not what you like".
This could have been the trouble with Spears's New York restaurant Nyla, which shut after a year in 2002 when the public failed to warm to its southern soul food, the speciality of Spears's native Louisiana. In its final months, Nyla switched to more sellable Italian classics, but still closed leaving more than $400,000 in unpaid bills and a reprimand from the New York City Department of Health for using dented cans of tomato paste.
But wait a moment - didn't Spears's ex-boyfriend Justin Timberlake co-develop his own southern restaurant in New York with far greater success? Called Southern Hospitality, the restaurant has done well enough to open a second branch. Harris blamed the discrepancy on the variation in the two stars' public profiles.
"Part of the success is timing - Justin Timberlake has kept a constant image throughout his career, he's kept his head below the parapet and you have to admire him for that," he said. "Britney Spears, on the other hand, has had massive highs and some disastrous lows. Not having that pristine reliable image may have worked against her."
Matching a celebrity's image with a restaurant that fits is also essential. The veteran rocker Alice Cooper got it right when he kitted out waiters in heavy mascara at his low-rent spot, Alice Cooperstown, in Phoenix, Arizona.
The superskinny supermodels Claudia Schiffer, Christy Turlington, Naomi Campbell and Elle Macpherson did less well at their 1990s venture the Fashion Café when they tried to pass off fattening comfort food as their own. "Naomi Campbell's Fish and Chips" was a notable menu howler.
Despite these many pitfalls, some celebrity restaurants do thrive. Robert De Niro, in particular, has made some particularly canny investments, notably in the exclusive Japanese restaurant group Nobu - with its memorable Dubai outpost - and in Manhattan's Tribeca Grill, which is decorated with paintings by De Niro's father.
As Harris says: "De Niro did a brilliant job with Nobu - he had a fantastic concept and then just let the experts get on with it."
If Jay-Z has anything to learn from the rocky history of celebrity restaurants, it's possible he hasn't learnt it yet. While 40/40's US website lists four branches, Forbes magazine claims that only one, in Atlantic City, is currently open, with the New York flagship under renovation. The Las Vegas branch of 40/40 closed in 2008 after just eight months, though for some reason the company claims selling the lease was "a great business decision".
Bearing this in mind, it might be a good idea for Jay-Z and Cole to heed Mark Harris's warning:
"Having a celebrity backer can be hugely useful, but restaurants drain money, and the bottom line is about managing staff and food costs, not PR."