The intruder at Prince William's party has been identified as a stand-up comedian who targets high-profile events.
Barschak targeted Ken Livingstone at a peace march
The father of Aaron Barschak, 36, said it was his son who had breached the security operation at Windsor Castle dressed as Osama Bin Laden.
His arrival at the castle drew the attention of police, and he was pictured shouting outside the gates before being led away by an officer.
Hours later he managed to get inside and - according to some party guests - apparently climbed on stage while Prince William was making a speech, before police intervened.
His father, Fred Barschak, 72, said he had recognised television pictures of his son handcuffed in the back of a police car.
Speaking outside his home in Kilburn, north London, the property developer told reporters his son was harmless and was seeking publicity for his comedy act.
Mr Barschak said: "I can believe
it was him. He would not have been trying to harm anyone, not at all.
"He is actually not at all anti-royal. He is a professional stand-up comedian who is desperate to be a serious
He added his son had probably wanted to make the headlines before his scheduled appearance at the Edinburgh Fringe festival.
Police would not confirm the intruder's identity but said a 36-year-old man from
London had been arrested on suspicion of burglary, which covers unauthorised
people entering premises.
When Mr Barschak first arrived at the castle, he was wearing a pink dress, turban, sunglasses and false beard, and shouting to reporters and gathering crowds outside the castle gates.
He said: "Happy
birthday. Out of Africa, I'm out of this world."
He then went on to publicise his performances at the Edinburgh Fringe Festival
in August, and lifted his dress to reveal another false beard and declare: "The real hair to
A uniformed policeman led him away from the crowds and towards the town centre.
Aaron Barschak regularly dresses up as the notorious al-Qaeda leader Osama Bin Laden and is known as "Comedy Terrorist".
Barschak's arrival at the castle caused a stir
His father said he had performed a similar stunt at Royal Ascot earlier in the week.
The comedian was pro-royal, he added, with a particular admiration for Prince Charles and his views on modern architecture.
Martin Mullaney, owner of the Cheeky Monkey Comedy Club in Birmingham, where Mr Barschak performed this year, said he was notorious on the comedy circuit for this kind of stunt.
He added: "I'd have him back tomorrow, because he would sell out the show."
Mr Barschak was educated at at the City of London school before
travelling to Bolivia and studying acting in New York.
He confronted London Mayor Ken Livingstone at the anti-war demonstration in Hyde Park earlier this
And Graham Norton was targeted while on stage during the London Comedy Festival.
He also interrupted Monty
Python star Terry Jones during a tribute show to Goon star Spike Milligan.
His father said: "He worshipped at the feet of Spike Milligan and says al-Qaeda is a girl's