Mr Justice Butterfield told the jury at Bristol Crown Court: "Here is a witness who first made public her allegations for payment of pounds 10,000 and stands to make a further pounds 25,000 if he is convicted ... If you think there is any reasonable possibility that she, either for the motives suggested to her or for any other motive, invented her account and came into this court and told here a pack of lies, you will disregard her evidence and find the defendant not guilty.
"But if you conclude that, despite all that, you are sure she has told the truth, you are fully entitled to rely on her evidence."
The 55-year-old singer, who is charged under his real name, Paul Francis Gadd, is accused of a series of sexual assaults on the girl. The jury of eight men and four women deliberated for four and a half hours before the judge discharged them for the night.
The judge warned the jury to disregard evidence they have heard about Mr Gadd being arrested at a PC World shop in Bristol in November 1997 after child pornography was found on his computer.
He said they should not necessarily put any weight on the fact that Mr Gadd did not give evidence during the hearing. "That is his right," he said.
But, he continued, the jury "may hold this failure against him" if, and only if, there was a case for him to answer.
Mr Gadd denies four charges of indecently assaulting an under-age girl. He also denies four charges of serious sexual assault against the girl.