The MI6 spy whose body was found in a padlocked hold-all in his bathtub sometimes went by a name other than Gareth Williams, his inquest heard on Wednesday.
But his mystery second identity was not revealed as the coroner cut short the line of questioning to a friend of the 31-year-old.
Elizabeth Guthrie was asked by Mr Williams's family lawyer Anthony O'Toole whether the spy had told her he "sometimes used another name", to which she replied "yes".
She also revealed that Mr Williams had used a number of different phones to call her.
"He wouldn't always call me from one number and he had brought various phones around," she said.
Ms Guthrie, who signed a police statement on which her name was also incorrect, described a friendship with Mr Williams based on their mutual love of history, art, Japanese Manga cartoons, travel and humorous anecdotes.
When police entered his home, they found some £20,000-worth of expensive women's clothing and shoes, the inquest at Westminster Coroner's Court has heard.
Ms Guthrie said she and Mr Williams had been planning to attend a fancy dress ball together, dressed as luridly-coloured Manga characters.
Asked if her friend had ever expressed an interest in cross-dressing, Ms Guthrie said: "Nothing of a sexual bent but we were going to a fancy dress ball together.
"He was going as a ninja, not as a queen."
She also suggested that his collection of female clothing might have been "Gareth's attempt at a support strategy for someone. They certainly would not have been for him."
Asked about his sexuality, she said: "I have a personal view that he was straight."
While the pair were close friends who spent lots of time together, Ms Guthrie said she had never been to Mr Williams's flat.
"For someone to have been brought back to his own space would have been something of note and would have implied, in my view, a very strong relationship," she said.
Williams was found dead in a Government flat in Pimlico in August 2010.
After excelling at university at mathematics, Williams worked as a cipher and codes expert at the Government listening station, GCHQ.
Williams was then seconded to work at the Secret Intelligence Service headquarters in Vauxhall, London.
CCTV captures Williams entering Holland Road Tube Station on the 14th August 2010.
Caught on CCTV at Holland Road Tube Station the same day.
Seen the next day on CCTV in Hans Crescent, London
His body was found in a holdall in this Pimlico flat on the 24th of August 2010.
Williams' funeral was attended by Sir John Sawers, head of SIS.
Screengrab from a video reconstruction showing a yoga specialist trying to lock himself in a sports holdall unaided
Screengrab from a video reconstruction showing a person trying to close the zip and padlock themselves in a sports holdall unaided