In March 2013, Bollywood was abuzz as Steven Spielberg came to town. At a glitzy gala to celebrate his visit to Mumbai, the world’s most famous film-maker mingled with a star-studded crowd and chatted on stage with legendary Indian actor Amitabh Bachchan.

Seated at a table alongside the two was the party’s host, the man who made the visit possible: Mr Spielberg’s business partner and “dear friend” Anil Ambani, then one of the world’s richest men.

The event cemented the reputation of Mr Ambani, the younger son of a corporate dynasty, as one of 21st-century India’s most glamorous tycoons. His foray into entertainment, including a tie-up with Mr Spielberg’s DreamWorks, added flamboyance to a business empire centred on telecommunications, power and finance. In 2008, Forbes named Mr Ambani as the world’s sixth-richest man with a fortune of more than $40bn.