Tulisa Contostavlos has denied being concerned with the supply of Class A drugs.
The N-Dubz star, 25, of Friern Barnet, north London, is accused of setting up an £860 deal for 13.9 grams of cocaine to an undercover reporter.
She appeared alongside rapper Mike GLC, also known as Michael Coombs, 35, of Velocity Way, Enfield, north London, at Westminster Magistrates Court.
He denied a charge of supplying the drug.
Contostavlos, who wore tight black trousers, a black top and black jacket, was forced to disclose her address to the court after her solicitor applied for it to be withheld to prevent "unwanted visitors".
But Chief Magistrate Howard Riddle ruled "the address must be given" after considering the application with representations from prosecutor Emma Scheer and the Press Association.
The singer then told the court: "Just to let you know, after it being read out, in the next month or so I might have to move to a new address."
Contostavlos is accused of being "concerned with the supply of 13.9 grams of cocaine" to the Sun on Sunday's undercover reporter Mazher Mahmood, sometimes known as the fake sheikh, between May 20 and May 24.
Coombs, who wore a blue jumper and black jeans, is accused of supplying the drug on May 23.
The pair will next appear at Southwark Crown Court in central London on January 9.
Contostavlos, who was represented by Ross Dixon, allegedly set up the deal after telling Mahmood she could help provide him with "white sweets", which the court heard was a code for cocaine.
She is accused of playing a "significant role" putting the fake sheikh in touch with Coombs before the pair met at the upmarket Dorchester Hotel in central London.
The Sun on Sunday recorded the meeting in which Coombs is said to have handed over half an ounce of cocaine for £860.
Contostavlos, who had blonde ringlets and looked tanned for the hearing, was initially arrested in connection with the incident with Coombs on June 4.
She was officially dropped as a judge on X Factor days before her arrest, with Sharon Osbourne returning to the show in her place.
The pair were given unconditional bail by Mr Riddle.