According to National Archive records, Hungarian-born Goldfinger was monitored by the Special Branch and MI5 due to his supposed links to the Communist Party.
Goldfinger, whose buildings include west London's Trellick Tower and his own home in Hampstead, north London, apparently employed a gaggle of lawyers in 1939 to help him gain citizenship, but he wasn't successful until 1947.
The revelation comes after the archived records were made public following a freedom of information request by the Camden New Journal.
Ernö Goldfinger's connections to the murky world of the secret service are a case of life mimicking art, as the architect was the inspiration for Bond villain Auric Goldfinger (below), created by author Ian Fleming, who lived nearby in Hampstead.
Fleming reportedly disliked Goldfinger's architecture so much that he decided to name one of his most famous baddies after him.
Ernö Goldfinger eventually became a British citizen and continued to work on an array of low-cost housing projects following the war.
Fleming's super-villain Auric Goldfinger was, on the other hand, sucked out of a plane.