The bride, Isha Ambani, is the Ivy League-educated daughter of industrialist Mukesh Ambani, thought to be India's richest man. Forbes estimates his net worth at over $43 billion.
The groom, Anand Piramal, is the relative pauper. His father, industrialist Ajay Piramal, is thought to be worth $10 billion.
The wedding is being held in Mumbai on Wednesday but festivities began weeks ago, starting in September with an engagement party at a lakeside Italian palace.