Entertainer and television presenter Rolf Harris touched a 13-year-old girl's breast after filming a children's TV programme and asked her "do you often get molested on a Saturday morning?", a court heard.
The Australian-born star, 87, is accused of groping the schoolgirl after he appeared in a broadcast of the BBC's Saturday Superstore in 1983, jurors were told.
Prosecutor Jonathan Rees QC told the jury of seven women and five men Harris approached the girl in the green room after filming of the episode, which also featured Wham!, had ended.
The lawyer said: "She recalls him sliding his open right hand across her back over her clothes and touching her breast.
"He then said 'do you often get molested on a Saturday morning?' which the prosecution suggests clearly shows the sexual nature of the touching."
The Animal Hospital host is standing trial accused of indecently assaulting three teenage girls in the 1970s and 1980s.
He is also alleged to have indecently touched a 14-year-old girl in 1971 after she asked him for an autograph at a music event for children in London.
The musician and artist is also accused of twice groping a third teenage girl after being paid £100 to appear on ITV celebrity show Star Games in 1978, and telling her she was "a little bit irresistible", the court heard.
Mr Rees added: "In essence the prosecution alleges that for his own gratification Harris groped these three young females in a sexual way, without their consent."
Harris appeared via videolink for his trial at Southwark Crown Court in London.
He denies four charges of indecent assault against three women between 1971 and 1983.