The jury at Southwark Crown Court heard how Rolf Harris was a "dirty old man" who assaulted a child at a community centre near Portsmouth at one point between 1968 and 1970.
The woman, speaking behind a screen, said initially she was confused and thought there must have been some kind of mistake:
It was very quick. In fact so quick that I thought, 'what's happened?'. The first time I thought, no, not deliberate. I thought, 'what's going on?', because there were a lot of people around and I didn't process what had happened.
She went on to describe how he repeated the assault, "more aggressively", and broke down as she said she "wasn't the same child" afterwards.
She said Harris had performed Two Little Boys at the event. Harris denies all 12 counts of indecent assault on four alleged victims.
It didn't matter if it was going to hurt me or not. It felt very agressive and I knew that it wasn't an accident.
More top news
The owner of a dog who was rescued from England's highest mountain is being sought by an animal welfare charity.
A vicar who was diagnosed with HIV after being attacked two years ago has created a powerful video to share her story with her congregation.
A man miraculously survived being shot near his home with a sawn-off shotgun when his mobile phone took the brunt of the blast.