A man who is accused of sexually assaulting a woman in Sydney's notorious Kings Cross handed himself in to police after his own mother dobbed him in after seeing him on a TV news report.

Police had released CCTV footage in an appeal to find a man they wanted to question over the attack in the early hours of January 20, 2014.

Their police description wasn't flattering; they were looking for someone with thinning hair, chubby cheeks, a long nose and a big belly.

View photos Police had released CCTV footage in an appeal to find a man they wanted to question over the attack in the early hours of January 20, 2014. Photo: NSW Police More

On that night, 37-year-old Roseville man Steven Robert Rundell was walking through a lively Kings Cross when he came across a young woman in a Pie Face shop. He found out she worked in Double Bay.

"I have friends who live in Double Bay," he said.

"Good for you," she replied, as she left the shop on the phone to her boyfriend.

It's alleged he then followed her up Bayswater Road and offered her a lift home.

"No, thank you, I don't need a lift home."

View photos The police description wasn't flattering; they were looking for someone with thinning hair, chubby cheeks, a long nose and a big belly. Photo: NSW Police More

He then allegedly wrapped his arms around her.

"You're really beautiful. Are you sure I can't offer you a lift home?" he asked.

Court documents allege this was the point where, as she tried to force herself away, he grabbed her between the legs and groped her.

"Seriously mate, you have to stop, I have a boyfriend," she begged.

She didn't run, according to court documents, because she didn't want Rundell to perceive that she was scared.

But she was. She was on the phone to her boyfriend but couldn't manage to speak because of her fear.

View photos Rundell has pleaded not guilty to a charge of sexual intercourse without consent, but guilty to a charge of indecent assault. Photo: NSW Police More

On Tuesday, Rundell pleaded not guilty to a charge of sexual intercourse without consent, but guilty to a charge of indecent assault.

He may face time behind bars during his sentencing on March 4 next year.