Tulisa Contostavlos said her life had been "ruined" for the last year by what she called "entrapment" from an undercover reporter working for the Sun.
Speaking outside Southwark Crown Court, the singer and former X Factor judge called on the police and the Sun's publishers, News UK, to look into Mazher Mahmood's conduct.
The judge in the case said there were "strong grounds" to believe Mahmood had "lied" and given "entirely inconsistent" evidence.
More top news
Fine start to the week for most but turning wet and windy from Wednesday.
Thousands of people have lined the banks of the Mersey to see Cunard's three flagship ocean liners sail down the river.
Claims that surgeons used an old saw found in a cupboard to amputate a patient's leg are being investigated.