Singer Pete Doherty has pleaded guilty to possession of cocaine, at Snaresbrook Crown Court.
He was charged after an inquiry into the death of filmmaker Robin Whitehead, 27, who was making a documentary about him.
Miss Whitehead was found dead in a flat in Hackney, east London, in January 2010.
Mr Doherty was granted unconditional bail and ordered to return to the court for sentencing on 20 May.
The singer, 32, of Marlborough, Wiltshire, said last year he was "shocked and saddened" by Ms Whitehead's death.
Meanwhile, Peter Wolfe, 42, of Heath Road, Maidstone, pleaded guilty to two counts of possession of cocaine and one count of supplying cocaine to Ms Whitehead, who died at Wolfe's east London flat.
Alan Wass, 29, of Bramley Road, west London, pleaded not guilty to possession of cocaine.
Judge David Radford described Doherty's criminal record as "unattractive".
Addressing the musician's lawyer Peter Ratliff, the judge said: "When someone constantly commits the same offence the law must be made very clear. Is your client aware he could face a sentence?"