The former Spice Girl is still angry with Murphy for dumping her while she was pregnant and denying that 14-month-old Angel Iris was his.
She told New!: "He never bothers with his daughter. I mean, what kind of man is that?"
She added that the actor's lawyers will be "vetting the lyrics closely" to ensure she does not make any statements which could be considered slander.
The song will feature on her forthcoming album, which also includes collaborations with Janet Jackson and Missy Elliot.