Actor Rob Lowe is to sue his former nanny after she tried to blackmail him out of $1.5 million (£750,000) by threatening to go public with allegations of harassment.

Explaining on blog website The Huffington Post, the West Wing star says the unnamed woman has worked for his family "off and on for seven years" and that she abruptly quit several weeks ago.

Lowe adds that he has since been told by one of her colleagues she had a "crush" on him and wished he would get a divorce from his spouse of 17 years.

The 44-year-old actor writes: "A former employee is demanding my wife Sheryl and I pay her $1.5 million by the end of the week or she will accuse us both of a vicious laundry list of false terribles.

"It is an attempt to damage and humiliate not only my wife and me, but our two young sons as well.

"My family is devastated at this betrayal; this woman worked in our home and traveled with us off and on for seven years, without complaint. In fact, she left other jobs to return to work for us three different times."

Lowe also claims that he is being targeted because of his famous name. He adds: "Everyone knows we live in a time where public figures are targets.

“But I also know of many people in everyday life who are paying the price of a climate where anyone can accuse anybody of anything, anytime, and hope for a big cash pay-off at the end. 'Hush money' to just go away. Well I won't go away. No one intimidates my family."