Adele reportedly requested £100,000 a minute to perform at a wedding.
The 'Skyfall' hitmaker was approached by South African fruit juice tycoon Vivian Imerman - who is worth around £400 million - to sing a 25-minute set at the nuptials of his daughter Megan at London's upmarket Grosvenor House hotel, but he decided against hiring the services of the award-winning superstar after discovering the brief performance would cost £2.5 million.
A source told the Daily Star newspaper: "Vivian is planning a lavish wedding.
"He paid Amy Winehouse thousands to perform at his eldest daughter Bianca's wedding three years ago. He hoped to do the same again with Adele.
"But he was surprised when he was told she'd cost £2.5m.
"Despite his bulging bank balance even he thought it was too expensive and is looking at other artists."
Despite missing out on the money from the wedding, Adele - who has five-month-old son Angelo with fiance Simon Konecki - is unlikely to be too disappointed as she is reportedly close to signing a £10 million deal to front an advertising campaign for a cosmetics firm.
She is said to be considering offers from Estée Lauder, L'Oréal and Dior to be the face of their brands, but will only accept if the ideas fit to her tastes.
A source told The Sun newspaper: "Adele is in big demand. She would only accept if the campaigns were to her taste and incorporate her music.
"The last thing she wants is a cheesy ad with a naff catchphrase.
"They would have to be in keeping with her personality.
"It's going to take a lot of persuasion to get her to agree but, right now, it looks as if she's close to signing a deal."
The 'Rumour Has It' hitmaker has previously admitted she was concerned endorsement deals could "taint" her image.
In a 2011 interview, she said: "It's shameful when you sell out. It depends on what kind of artist you wanna be, but I don't want my name anywhere near another brand.
"I don't wanna be tainted or haunted."