Simon Cowell's Ex-Fiancee Mezhgan Hussainy -- NO Plans to Write a Tell-All

Simon Cowell's ex-fiancée, Mezhgan Hussainy, has absolutely no plans to write a scathing tell-all book about everyone's favorite acerbic judge, despite reports to the contrary ... TMZ has learned.

British tabs are buzzing today with a report that Hussainy is out of "revenge" against Cowell and plans to pen a book and reveal all the couple's dirty laundry.

But a source close to Hussainy tells TMZ she is "not the type of person" to write such a book and that Hussainy and Cowell are still very close ... despite breaking off their engagement last year.

A rep for Hussainy tells TMZ she "has absolutely no plans to write a book of any sort."