Sir Paul McCartney's estranged wife Heather Mills has denied she is planning to write a book of sex tips - insisting she is far too focused on her charity work for such a project. The former glamour model was reportedly penning a sex guide for women - a follow-up to her recent self-help book Life Balance: The Essential Keys To A Lifetime Of Wellbeing, which was released in 2006. The 39-year-old was revealed to have posed for a variety of raunchy photoshoots during her modelling career including pictures for an X-rated magazine. However, a representative for Mills has rubbished rumours of a book insisting, "Right now she is counselling cancer children in the U.S. and trying to facilitate a bone marrow transplant to a young mother so that this mother can live. That is the story of her life."