Jessica Simpson is refusing to make her fiance sign a prenuptial agreement.

The singer-and-actress - who got engaged to NFL player Eric Johnson on Thursday (11.11.10), six months after they started dating - has reportedly angered her father-and-manager Joe by her refusal to draw up an agreement detailing how the couple's assets would be divided if they separated.

A source said: "At the moment, Joe is sitting back and being a great father supporting his daughter and his future son-in-law.

"However, you can bet after all the excitement has died down, Joe is going to do everything in his power to make sure Jessica doesn't walk down the aisle until Eric signs away any right he might have to Jessica's enormous Fortune."

Friends of the 30-year-old star - who has an estimated wealth of around $100 million - are said to be particularly concerned about her decision not to make Eric sign a prenuptial agreement because she also refused to make a similar agreement when she married Nick Lachey.

When their divorce was finalised in June 2006, Nick walked away with a substantial amount of her finances.

The insider told website PopEater: "Nick walked away with over $10 million of her money when they divorced, because they had no prenup. You would think she would have learned her lesson. But where romance is concerned, Jess' follows her heart not her head."

Joe recently took to twitter to congratulate her on her engagement.

He posted: "So very happy for Jess and Eric. May they have a lifetime of joy and happiness."