NEW DELHI -- In a season of big Indian weddings, the Wednesday marriage of the scions of two billionaire families might be the biggest of them all.

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. Over the weekend, thousands attended pre-wedding parties at a 16th century palace in the Indian desert city of Udaipur, where videos shot by partiers showed Hillary Clinton dancing with Shah Rukh Khan, one of India's biggest movie stars, as former U.S. Secretary of State John Kerry danced just a few feet away.

A highlight was a performance by Beyonce, who sang "Crazy In Love," among other hits, with a band backing her up and a series of costume changes that included at least one India-inspired outfit.

"Beyonce Lights Up Udaipur," the Times of India shouted in a Tuesday headline.

Indian weddings are famously elaborate, driving many families into debt with expectations that they invite hundreds or thousands of people, and arranging professional song-and-dance shows.

Among India's rich, weddings are displays of almost unimaginable wealth, with guests flown in on chartered jets from around the world and celebrities paid hundreds of thousands of dollars for brief appearances. In 2004, a daughter of Indian steel baron Lakshmi Mittal held her engagement party at Versailles.

The Indian media noted that the actual Ambani wedding, in Mumbai, was expected to be a relatively small affair, with just 600 or so people in attendance. More parties will follow the marriage ceremony.

Antilla, the Ambanis' 27-story Mumbai home, has been strung with lights for the wedding, looking like a small skyscraper at night. The family is said to have reserved hundreds of hotel rooms for their guests.

Indian grooms traditionally ride to their weddings on horses, but Piramal arrived at the Ambani home in a classic Rolls Royce, with marching bands playing alongside.

The Ambani fortune stretches across a range of industries, from petroleum to chemicals to mobile phones. They control the conglomerate Reliance Industries. The Piramal family businesses include pharmaceuticals and real estate.

The competitiveness of India's wintertime wedding season is growing more extreme, according to Archana Dalmia, a social activist in New Delhi.

"A farmer might commit suicide because he can't save enough money to get his daughter married," she said.

The extravagant wedding of Indian actress Priyanka Chopra and American singer Nick Jonas earlier this month -- attended by Indian Prime Minister Narendra Modi -- was straight out of a Bollywood film.

So-called dowry deaths -- brides killed when their families fail to meet in-laws' dowry demands -- constitute a substantial share of all female homicides in India, a 2018 United Nations Office on Drugs and Crime report found.

While opulence has always been a feature of Indian weddings, families used to hand down bridal saris as heirlooms. No more, Dalmia said.

"This generation is very different. Priyanka Chopra will never be able to wear it again and she won't be able to pass it down," Dalmia said.