The woman previously could not recall making the phone call.
She said she had not followed Harris' earlier trial closely but was "triggered" to make the complaint after an inquiry into child sex abuse by former British celebrity Jimmy Saville.
"This is something that's been on my mind for absolutely years and years, but I haven't had the courage to come forward," the woman told the hotline in the recording played to the court.
"But seeing this in the news, it's just run thoughts through my head and I've been pushed by friends for years to say something and I haven't said anything."
The woman, who gave evidence by video link, came close to tears as she denied suggestions by Harris' defence barrister that money played a factor in her decision to make the complaint.
"No, I work full time," she told the court.
Defence lawyer Stephen Vullo QC also suggested that Harris' "smirk" could have simply been a "smile" and a sign "he was happy" to be at the theatre with hundreds of fans.
The woman was among those who obtained an autograph from Harris and was photographed with him.
Under cross examination, she said she must have followed other people to receive the autograph and denied later buying a copy online.
The woman said she told her father about the attack on the day and he confronted Harris. Her father has since died and her mother has dementia and cannot give evidence.
One school friend who was in the same youth band told the court she saw the then-14-year-old girl sit on Harris' knee and remembered it because she "thought it wasn't right".
Another former member of the band who was at the 1971 event gave evidence that he saw the then-girl crying and "in a state of distress". He also said he remembered the girls' father was "red faced" and angry.
Neither person said they witnessed the alleged assault.
Harris has pleaded not guilty to the attack, which is one of seven new counts of indecent assault and another count of sexual assault against seven girls and women that he is facing in court.
The complainants were aged between 12 and 42 at the time of the alleged assaults between 1971 and 2004.
The Australian-born TV star watched the proceedings via video link from prison, where he is serving time for his previous convictions.
At one point, his defence barrister told judge Alistair McCreath the 86 year old former entertainer was "struggling" to sit for long periods of time.
Harris thanked the judge after he told the court the accused could stand or take a "comfort break" if needed to.
The case continues.
