The music mogul popped the question on Valentine`s Day, presenting Mezhgan with a £250,000 diamond engagement ring. They are currently planning their nuptials, which it is understood will take place later this year, and have also agreed to sign an agreement to safeguard Simon?s fortune.

It is believed the prenup will see Mezhgan receive £33 million if the marriage lasts less than five years. She will get an extra £700,000 for every year they are together from then on.

"It`s a win-win situation for Mezhgan and she`s already verbally agreed to it," a source explained to Look magazine. "Now it`s just a matter of the lawyers signing it off."

Simon is also said to have agreed to buy Mezhgan a house costing the same or more than the one they are living in if they split.

The 50-year-old decided to arrange the legal document to safeguard his estimated £170 million fortune - which doesn?t include his cars or properties. After signing a new deal with Sony records which made him joint owner of Syco records, Simon is on course to net around £70 million this year.

He apparently understands a prenuptial agreement can be seen as unromantic, but has assured Mezhgan he thinks they will be together forever.

"He`s been flooding her with love letters, sexy texts and a daily delivery of 24 roses," a source added. "Simon loves that Mezhgan`s an independent woman. She tries to pay her way at dinner, and when she moved into his Beverley Hills mansion, she even offered to contribute towards the mortgage. There`s no way she wants to be seen as a gold digger."
sections: Celebrities