Cee-Lo Green has pleaded not guilty to possession of ecstasy.

The 'Voice' US coach has claimed he's innocent after being charged with slipping the illegal substance into a woman's drink during a date at a sushi restaurant over a year ago, which led to the pair ending up in bed together.

Cee-Lo was caught on tape by the woman in question and can reportedly be heard referencing the drug.

The criminal complaint claimed the 'Forget You' singer never intended to harm the woman when he shared the substance with her, but if he is found guilty he could face up to four years in prison.

Cee-Lo - real name Thomas DeCarlo Callaway - was ordered by Judge Shelly Torrealba to return to court on November 20 for his preliminary hearing.

The 33-year-old woman insisted the 'Crazy' hitmaker had sexually assaulted her during the incident, but the Los Angeles County District Attorney (DA) rejected the sexual assault case yesterday (21.10.13) due to insufficient evidence.

Law enforcement sources told gossip website TMZ: ''Authorities had problems with the woman's story ... one of which was that she and Cee-Lo had been dating for months and had already been intimate.''