An ex-Boyzone pop star has told jurors of the alleged abuse he suffered at the hands of a "manipulative" ex-girlfriend accused of murdering her French nanny.
Pop Idol Vietnam judge Mark Walton flew in to the UK from Los Angeles to give evidence at the Old Bailey trial of fashion designer Sabrina Kouider.
The 35-year-old mother and her partner Ouissem Medouni, 40, are accused of murdering au pair Sophie Lionnet and throwing her body on a bonfire at their home in Wimbledon, south west London.
The couple had allegedly tortured the 21-year-old into "confessing" to being in league with Mr Walton in connection with drugs and abuse at the household.
But Mr Walton said the first he knew of Miss Lionnet was when murder squad detectives contacted him in September last year.
He told how Kouider had been "abusive" and "exhibited a manipulative and controlling nature" with a "calculating streak".
He had previously described her as a "really gentle, sweet, loving" person who could become "quite scary" in seconds.
He told jurors: "Sabrina shared some stories from her past.
"I guess knowing that, I felt it brought us closer together at times, but it was turbulent, probably the most turbulent relationship I had ever been in.
"She would go from softly spoken French accent then she would flip, get very angry, very loud and just not care where we were.
"She would just go crazy over something trivial."
The wealthy music mogul supported her financially through the highs and lows of his successful career.
Having created Boyzone in 1993, he found success with Fifth Avenue and more recently as a judge on Vietnam Pop Idol.
The softly-spoken Irishman said he met Kouider in a NatWest bank in Notting Hill in 2011 and hit it off straight away.
He said: "I was in love. She was my life then so..."
He gave her thousands of pounds a month, paid for nannies and even covered £12,800 in rent after she had left him, the court heard.
Kouider fired her nannies, accusing them of stealing or being attracted to her "friendly" boyfriend, the court heard.
The musician said they lived together for two years in Queensway, London, before she disappeared and they split up.
Referring to outlandish accusations levelled at him by Kouider, prosecutor Richard Horwell QC said: "Have you ever been party to a plot to drug the people in the Wimbledon flat and whilst unconscious sexually abuse the occupants?"
Mr Walton said: "Absolutely not."
Orlando Pownall QC, for Medouni, said: "You must have asked yourself many times where did it go wrong?"
While they were together, Kouider would fly into a rage, even shouting in Oxford Street "the Boyzone's broken - he's got no money" as they shopped together, the court was told.
In 2012, police had been called a number of times over various accusations, including that he had photos of another woman on his phone, jurors heard.
Her complaints ranged for "mistreating" a cat, walking into the house with "muddy" shoes and stopping her from seeing friends.
After Mr Walton stopped paying her rent in 2014, she took out a non-molestation order claiming harassment, the court heard.
She also rang his mother in Dublin, contacted his business partners and created a fake Facebook page accusing him of being a "paedophile", he said.
Mr Walton told jurors: "I was broken, emotionally broken but I loved her."
Icah Peart QC, for Kouider, suggested Mr Walton was a very wealthy man, even being described as a billionaire in one media report.
Mr Walton denied he was that rich, but added: "I'm doing okay."
Kouider and Medouni have admitted perverting the course of justice but deny murder.