A former employee of R Kelly claims to have recognised the R 'n' B star in a video allegedly showing Kelly having sex with an underage girl.
The I Believe I Can Fly star is accused of filming himself engaging in sex acts with a girl who prosecutors say may have been as young as 13 at the time.
And Lindsay Perryman, his former personal assistant, told jurors at the Chicago trial that she was "110 per cent" sure that he was the man seen in the footage.
"I did not want to believe it was Mr Kelly," Ms Perryman told the jury.
"I think so highly of him and his family, they have been so good to me."
The 26-minute video allegedly showing Kelly and an underage girl was shown to jurors at last week, with Cook County prosecutor Shauna Boliker warning the jury they would see footage of an "underage child performing sex acts that you have never seen before".
Ms Perryman said that, should the man in the video be proved to be R Kelly, she would be surprised as it would signify out-of-character behaviour.
"I have never seen him being inappropriate," she explained.
"He treated me and the people who worked for him well."
The singer's legal team claims that the video depicts neither Kelly nor the alleged victim.
Kelly's lawyer Sam Adam Jr described the tape last week as "at best a copy of a copy of a copy" and claimed that neither the FBI nor "a single witness" could conclusively identify his client as the man in the tape, according to the Associated Press news agency.
Bennie Edwards Jr, a cousin of the alleged victim, said the video "favoured" the allegation that his cousin and Kelly were the people shown in the footage but said he could not say for certain.
The trial continues.