Britney's fiancé Sam Asghari 'demands more money' before wedding can go ahead

Britney Spears is busy with preparations for her wedding - but behind the scenes she's reportedly letting lawyers prep her prenup to protect her estimated $70million fortune.

The Baby One More Time singer and fiancé Sam announced their engagement after five years together and last month confirmed she is expecting their first child together.

But according to a source, they are still in the process of hashing out their prenup before the wedding can take place.

"The talks have been a little longer than usual", a source told Heat Magazine of the alleged arrangement.

"Sam wants substantial increases for every five years they are married, should it end."

Britney is reportedly taking a backseat according to the same source and letting her lawyer handle the potential prenup as she is focussing on her health and pregnancy and planning their wedding.

Proving he's still happy to make light of what could potentially be an awkward situation as he joked about a prenup in an Instagram post.

Britney and Sam are expecting their first child together - 15 years after she last gave birth (Getty Images)

Britney and actor Sam have been together for five years and have proved they are a strong couple through her conservatorship struggles which finally ended just months before they got engaged (Britney Spears/Instagram)

Sharing the post he penned: "Thank you to everyone who is concerned about the prenup. Of course, we're getting an ironclad prenup to protect my Jeep and shoe collection in case she dumps me one day."

But the pop princesses fans who proved without doubt they have her back with their Free Britney movement, which later led lawyers to free her from a 13 year conservatorship to finally control her own future (and finances), are keen to see her protected by a prenup.

Oscar winning actress Octavia Spencer commented. "Make him sign a prenup,"

Another commented: "Still don’t know about the dude Sam so protect your assets Britney! Make sure to get that prenup girl!"

A third quipped: "THIS IS A STORY ABOUT A GIRL NAMED PRENUPNEY.”

A fourth urged: "Please make him sign a prenup."

Britney is set to wed Sam Asghari after he proposed last September (Getty Images)

According to Celebrity Net Worth, Britney is worth $70 million, a drop in the ocean compared to Sam who is worth $1 million according to The Sun, which includes income from his acting and modelling career.

Sam has starred in TV shows like Black Monday, NCIS and Hacks and is the founder of his own fitness website, Asghari Fitness.

Britney was previously married to Kevin Federline, who she has two children with, Sean Preston, 16, and Jayden James, 15.