Rob Lowe exposed himself to a former nanny and touched her inappropriately, she claimed. The 24-year-old Jessica Gibson, who worked for the actor and his wife for seven years, made the allegations in a lawsuit filed on Monday.

Between September 2005 and January 2008, Lowe "placed his hand inside Gibson's pants in order to touch her crotch" and "grabbed Gibson's buttocks without consent" several times, the 18-page legal document claims.

Gibson also alleged harassment on the part of Lowe's wife Sheryl who, the nanny claims, discussed her sex life with the 'West Wing' actor, made vulgar comments and walked around naked.

Lowe last week claimed that Gibson had demanded $1.5-million from them by 11 April or she would reveal the details of her harassment claims. He called the alleged extortion "an attempt to damage and humiliate not only my wife and me, but our two young sons as well".

In the wake of Gibson actually filing the lawsuit, Lowe's attorney has rejected the ex-nanny's allegations.

"Ms. Gibson's older sister worked for the Lowes for seven years. Ms. Gibson worked for the Lowes on and off for seven years. She left at least two times, to pursue other jobs, and returned each time asking for more hours. She sent two emails the day after she left, both saying she loved the Lowes and her leaving had nothing to do with them but her heart wasn't into being a nanny anymore. This is totally inconsistent with her latest allegations. An investigation of dozens of present and former employees has failed to find one single person to verify her allegations. The allegations in the complaint are simply untrue," said Stanton 'Larry' Stein on Tuesday.

Gibson has hit back through her own attorney: "We don't think so," responded Gloria Allred.

Gibson, who quit her job at the Lowes on 24 February, had only returned to work previously because "I love the children. I needed the job. I thought it would get better, and I was scared."