Charlie Sheen's troubled ex-wife Brooke Mueller has been hit with a lawsuit from a former nanny who alleges she is owed up to $10 million (GBP6.6 million) in unpaid overtime wages. Norma Lavizzo, who previously took care of Mueller's kids, is claiming she worked way over her scheduled 40-hour weeks, but received zero overtime pay, according to TMZ.com. In the suit, Lavizzo alleges she was put on call by Mueller and had to make herself available 24 hours a day. She also claims she worked non-stop during a four-day family trip to Miami, Florida. The former nanny apparently attempted to settle the matter with Mueller privately before filing suit, but her negotiations did not succeed and she's now asking for $10 million. The reality TV star's problems are beginning to pile up as she battles for custody of her twin sons after a rehab stint - she has been forced to move out of the home Sheen bought for her as her brother moves in to look after her sons. In May (13), the four-year-old twins were placed in the care of Sheen's second ex-wife, actress Denise Richards, after Mueller lost custody of them following a drugs bust that prompted her to check into a rehabilitation facility. Last week (05Nov13), Richards insisted she could no longer take care of the kids because they were terrorising her daughters and pets. The boys were handed over to Mueller's brother, Scott Mueller.