The former model, who split from McCartney in May (06), has recently been accused of appearing in a "hardcore porn" shoot for a German book, as well as working as a high class prostitute before her marriage to the BEATLES legend. She denies both charges.

Now she'll have to battle two more allegations of appearing in X-rated US sex guide SEXUAL SECRETS and an explicit French magazine, according to British tabloid The Sun.

A pal tells the newspaper the latest revelations are set to sicken her estranged husband: "This will be yet another bombshell for him.

"Heather always insisted her modelling past just included a sex guide. But Paul's since been made aware just how pornographic some pictures are."