They were words of wisdom from one billionaire to another - whatever you do, make sure your intended signs a pre-nuptial agreement before you marry.

But when Mark Zuckerberg wed his long-time girlfriend, a day after the stock market in New York valued Facebook at $US104 billion ($105.7 billion), it was unclear whether he had taken property mogul Donald Trump's advice.

Like the rest of the world, Trump was unaware of Zuckerberg's forthcoming marriage to Priscilla Chan when he mused on the implications for their relationship of the 28 year-old's wealth following Facebook's public flotation.

With a 28 per cent stake in the company, Mr Zuckerberg's worth stands at more than $US19billion .