Tulisa Contostavlos has appeared at Chelmsford Magistrates court accused of assaulting a celebrity blogger at V Festival in 2013.
Savvas Morgan (Vas J Morgan) claims that the singer and former X Factor judge attacked him backstage at the music event held in Chelmsford on 18 August.
Morgan alleges that the N-DUBZ star was in a "drunken and angry state" when she charged at him and punched him in the face in an unprovoked attack.
The 25-year-old, who scored a hit with dance track Young, arrived at the hearing in an all-black outfit. She denies the allegations.
"Tulisa strongly denies assaulting Mr Morgan. She specifically denies punching Mr Morgan in the eye," a spokesperson previously said.
"She has placed this matter in the hands of her lawyers for immediate and appropriate action."
Contostavlos pleaded not guilty in a previous hearing in February. The trial is expected to last two days.