Reliance's efforts, coupled with posts from a host of Bollywood stars and coverage in media, have helped whip up public interest in the wedding, overshadowing some critical social media posts that have questioned the opulence at a time of growing inequality in India.
Ambani's youngest son Anant, 29, is marrying his long-time girlfriend Radhika Merchant, 29, in a star-studded ceremony in Mumbai that will be attended by celebrities and politicians, such as Kim Kardashian, Mike Tyson, Tony Blair and Boris Johnson. Three days of celebratory receptions will follow.
One unnamed executive at Reliance called the event a "powerful symbol of India's growing stature on the global stage."
"The presence of esteemed individuals highlights India's economic, political, intellectual, and scientific prowess," the note, shared with reporters, said.
Ambani, Asia's richest person, is famous for hosting lavish parties, especially for his three children Akash, Isha and Anant. International artists perform and a host of Bollywood stars usually attend the gatherings, whose price tag runs into the millions.
This promises to be the most extravagant of Ambani's galas so far, although it is not know how much was spent.
Reliance shares videos, photos
Some, such as opposition politician, Thomas Isaac have called the amount of spending "obscene."
"Legally it maybe their money but such ostentatious expenditure is a sin against mother earth and (the) poor," he said in a post on X.
The wedding functions have been deemed a public event, leading to traffic restrictions in a key Mumbai business district for four days, also raising public ire.
With access limited and details closely guarded, information meted out to the eager public has been done partly through Reliance's official Facebook page, which has 2.3 million followers.
The account shared video clips of dance performances and photographs to give a peek into the private celebrations.
One post, opens new tab on Reliance's Facebook account this week, which received 54,000 likes, showed the Ambani family at a private music function, dancing to a Bollywood song, which feature in most Indian marriages. It was promoted with hashtags such as #ARWeddingCelebrations.
Media access to the wedding venue was restricted on Friday night, with only a limited number of photographers and TV crew allowed to capture incoming guests.
Onlookers stood with umbrellas in rain outside the venue, some clicking pictures, with the sound of Bollywood audible from inside.
A foreign company executive in India, who is due to attend the Ambani wedding function this weekend, told Reuters function organisers will likely put tape on the phone camera of entering guests to ensure no pictures are taken.
Most of Ambani's celebrations are closely guarded.
The wedding events started in March with a three-day pre-wedding party with 1,200 guests and a performance by superstar Rihanna, followed by a European luxury cruise with 800 guests in May.
Days later, several Bollywood actresses posted photos on Instagram, sporting luxury designer labels, to their millions of followers, without any details of the Ambani cruise celebrations.
Such is the interest, Indian TV news channels are tracking the wedding minute-by-minute.
"The world descends ... Guest list to what's there to eat. Every minute detail on Times Now," the TV news channel's tickers said on Friday evening.