Tulisa Contostavlos has urged police to investigate undercover reporter Mazher Mahmood - known as the 'Fake Sheikh - and "put an end to his deceits".
She was speaking after her trial on drugs charges collapsed with the judge telling jurors there were "strong grounds to believe" that Mr Mahmood had "lied" at a pre-trial hearing.
More top news
A man is facing jail for killing his toddler son by force-feeding until he "drowned in his food"
The quartet are to work on a 'ground-breaking' project with former Spice Girls manager Simon Fuller.
At least 17 people are dead after an airstrike outside a school in Syria, activists said.