"Someone might as well have told me my father was an alien, or a woman! I just could not believe it."
Pierre Boom's life has been turned upside-down by his father's spying
For Pierre Boom, the memories are still fresh of the day in 1974 when, as a 17-year-old, he learned he had been living a fiction.
He was not, as he thought, a normal West German teenager.
Instead, he was the son of two East German spies.
"At 6.32am there was a police raid on our house," he recalls.
"My parents and my grandmother were taken away. I was left alone in the house with loads of police and federal agents.
"They searched the flat, took pictures from the walls, cut off samples of our soap, and even took away some of my music collection.
"It went on for hours before they told me what was going on."
Pierre Boom's parents were agents of communist East Germany.
His mother was a small-time player, but his father was involved in the biggest political scandal in West German history.
That same day, television reported that Chancellor Willy Brandt's closest personal aide, Guenter Guillaume, had been arrested for spying.
This was Mr Boom's father - he changed his name in later life.
The revelations led to Brandt's resignation as chancellor, a story that is now the subject of renewed interest in Germany.
The British play "Democracy" has just opened in Berlin. It focuses on the relationship between Brandt and Guillaume.
There has also been a German TV dramatisation.
Germans are fascinated by the spy scandal that toppled Willy Brandt
And the renewed attention has unearthed some untold stories - like Mr Boom's.
"Suddenly, East Germany - the GDR - came into my life," he said.
"Guys from the embassy came and told me it was all true about my parents, and that they'd look after me.'
Several weeks later Mr Boom was in East Berlin, seeking answers.
He decided to stay there, on the advice of his father's lawyer that if his parents were sent back he would be unable to visit them if he stayed in the West.
No happy ending
Over the next seven years he visited his parents regularly in their West German prison, but felt increasingly unhappy about his life in the East.
"I tried to settle," he said. "But the East didn't become my home, and in 1980 I told the guys from the Stasi (East German secret police) that I didn't want to live there any more.
"The result was that they took my passport and I couldn't travel! So I became a real Ossie, a real East German."
Shortly afterwards, Mr Boom's parents were released.
But this was not the happy end he had hoped for.
His father dismissed his questions about what had happened, and right up until his death in 1995 it was impossible to rebuild the relationship.
"As a son I tried to put the different identities of my father into one. But I didn't succeed," said Mr Boom.
"I still have different fathers: one father before my parents were arrested, a father in jail, a father in the GDR."