BY MIKE IVES AND VINDU GOEL

    Indian weddings are known for being long and elaborate. But by any measure, the weeklong celebrations for Isha Ambani, the daughter of perhaps Asia's richest man, are on another level — or planet — of extravagance. Ms. Ambani, 27, is to be married to her childhood friend Anand Piramal, 33, a real estate developer and scion of another of India's most prominent business families, this week in Mumbai. Their weeklong bash is said to include at least five events, and there has been much speculation about the cost of luxury hotel rooms, chartered flights, catered meals and entertainment. Bloomberg reported an estimate of $100 million, but a person close to the family has disputed that number. Calculations based on publicly available prices suggest a bill closer to $15 million.

    In Britain, Prince Harry's wedding to the American actress Meghan Markle cost $40 million, in a country where labor costs are much higher. But whatever the price, the Indian wedding would be small change for the father of the bride, Mukesh D. Ambani, a tycoon with an estimated net worth of $42 billion. His businesses — in oil, telecommunications, chemicals, textiles, technology and food — touch the lives of every Indian, and his daughter's wedding is the subject of intense public fascination. Indian weddings have in recent years become a symbol of the country's new moneyed elite, said James Crabtree, the author of "The Billionaire Raj: A Journey Through India's New Gilded Age." "Of course, a wedding of the pre-eminent corporate dynasty of modern Indian history is going to be a very big and very extravagant deal," he said. The pre-wedding festivities hosted by Mr. Ambani and his wife, Nita, began on Saturday in Udaipur, a northern Indian city famous for its palaces, and drew celebrities from around the world. The A-list guests included the former secretaries of state Hillary Clinton and John Kerry, who reportedly danced to bhangra, a type of pop music from India's Punjab region. 

    Oh, and Beyoncé flew in to perform a 45-minute private concert, with several costume changes. (At one point, the Bollywood megastar Salman Khan appeared on stage behind members of the Ambani family, prompting some to joke on Twitter that he had been relegated to the role of backup dancer.) Saturday's event overwhelmed Udaipur, as the Ambanis' guests took over the city's hotels and clogged its tiny airport. Even Mumbai's international airport set a record for traffic on Saturday, as dozens of private chartered flights made their way north. One wedding guest, who did not want to be identified discussing the Ambani family's private affairs, said that invitations came in a Dolce & Gabbana box, adorned with pink and gold lace and detachable chains that could be worn as jewelry. She added that the Udaipur event appeared to have about 2,000 guests. One highlight was a Bollywood dance number that the bride's mother, Nita, performed with her two sons, Akash and Anant. Mukesh Ambani's father, Dhirubhai Ambani, was a schoolteacher's son who created a business empire in India at a time when most large-scale private enterprises there were stifled by government controls. His firm, Reliance Industries, eventually came to be seen as the face of India's industrial renaissance. The wedding ceremony was to take place at Mukesh Ambani's 27-story home, which towers over southern Mumbai and includes a six-level parking garage and three helipads.