LOS ANGELES, US - A FORMER nanny for actor Rob Lowe has countersued the couple, claiming she was sexually harassed while working for them in 2007 in a case filled with sordid accusations and a claim of extortion.

It is the second time that Lowe, 44, who stars in US television drama Brothers & Sisters, has been sued since he and his wife, Sheryl, filed their own suit against two former nannies and a chef claiming the three violated confidentiality agreements by divulging personal information about the couple.

In the latest suit filed in Los Angeles Superior Court on Wednesday, former nanny Laura Boyce claims that Sheryl Lowe subjected her to 'sexually offensive and hostile conduct' by walking around at home naked in front of Ms Boyce and asking Ms Boyce questions about her sex life.

Ms Boyce also claims she regularly worked 15-hour days without being paid properly for her overtime. She worked for the couple last year from April through November, helping to care for their two teenage sons.

'We are on top of this ... and we are not going to stop until there is justice,' Ms Gloria Allred, Ms Boyce's attorney, told reporters at a news conference as Ms Boyce stood close by with tears in her eyes.

Last month former nanny Jessica Gibson countersued the Lowes, saying that Rob Lowe stuck his hand into her pants, grabbed her bottom and exposed himself to her.

Ms Allred, a prominent attorney in high-profile Hollywood cases, also represents Ms Gibson.

In an April blog posting when the Lowes initially sued, Rob Lowe wrote that one of the nannies demanded US$1.5 million (S$2 million) from the couple, or she would 'accuse us of a vicious laundry list of false terribles'. He did not say which one.

In a statement released to celebrity television show The Insider on Wednesday, Sheryl Lowe called Boyce's lawsuit baseless.

'The charges against me are lies meant to embarrass and humiliate. I find it deeply offensive the false allegation that I would use racially insensitive comments,' she said.

Lowe rose to fame in the 1980s in films such as The Outsiders and St Elmo's Fire. But he suffered a setback in 1988 when a videotape surfaced showing him having sex with two young women, one of them a teenager.

He rebounded on stage and television, and eventually won a starring role in Emmy-winning TV show, The West Wing that returned him to Hollywood's limelight.

Sheryl Lowe, 46, was a television and film makeup artist.

The two have been married since 1991. -- REUTERS