A teen actor raped a 14-year-old boy while his girlfriend blocked the escape and told him to “do it”, a court has heard.

Blackfriars Crown Court heard on Monday how a South London actor orally raped a 14-year-old boy in a London theatre to prove to his girlfriend he was bisexual.

The defendant, who was then 15, allegedly dragged the teenager he attends stage school with down a stairwell in a London theatre in July 2010 and performed a sex act on him.

The next day, the actor - who cannot be named for legal reasons – orally raped the boy in a fire escape while his girlfriend blocked the doors, the jury heard.

As the boy described a second attack yesterday he said: “He told me that we needed to show her.

"I said ‘we don't need to show her anything, I want to get out’.”

Timothy Forster, prosecuting, asked the boy whether he could get out but he replied: "No (the girlfriend) was sitting against the doors.

"She was saying 'Do it for me'. I told her I don't want to."

The court heard how the attack only stopped after the boy bit the defendant, forced his way out and ran away.

The boy added: "I was scared so I ran up to the door and forced it open and ran up to the gods.

"I felt sick. I was scared but I just stayed behind the teachers because I felt safer if my teachers were there.

"I was just scared and worried what people would think. I was more upset I wouldn’t know how to say it."

While giving evidence on Monday, the alleged victim, now 17, collapsed behind a curtain and the court was cleared so he could receive medical treatment.

The defendant, also now 17, is facing one count of oral rape and three counts of sexual assault between July and September 2010 while the pair studied at the same stage school.

Mr Forster said the attacks started after the defendant’s girlfriend had asked him about his sexuality and he approached the boy saying: "I think I’m bi".

When the school returned after the summer holidays the abuse allegedly started again and the court heard the boy was assaulted in the toilet and in the men’s changing room.

The prosecutor told the court that incidents took place on a weekly basis over a six-month period, "none of which he wanted".

The court heard how the boy did not tell anyone of the abuse at first because he was "shocked and ashamed".

The defendant has denied the charges and the trial continues.