STARING at the computer screen, a chill ran down Chaz Bono's spine as he read the latest sinister threat: "I will kill you. I have a gun."
With pop legend Cher for a mum, the 43-year-old is used to unwanted attention from strangers.
But in the run-up to his appearance on a hit US TV show, his Twitter messages took a menacing turn.
Looking back, Chaz is not surprised by all the furore that blew up when he took part in Dancing With The Stars last year.
Photos from his childhood show him as a bright-eyed blonde girl - a stark contrast to the burly, 20st, bearded, tattooed bloke he is today.
The only child of pop duo Cher and the late Sonny Bono, Chaz was born female and originally known as Chastity.
But two years ago, after years of unhappiness which led to a descent into prescription drug abuse, he "transitioned" to become male.
A new documentary, Being Chaz, charting the highs and lows of his life as the world's most famous female to male transsexual, is on next week.
It includes coverage of the furious backlash whipped up over a transsexual man appearing on prime-time TV, in the American version of Strictly, and the hate-filled messages from strangers that shook Chaz to the core.
Even today, relaxing in his LA home with his two dogs and three cats, Chaz's memories of those vicious threats are still vivid. And he hopes that the British response to his latest telly project, which will be shown here next Wednesday at 10pm on Discovery Real Time, will be more sympathetic.
In an exclusive interview with The Sun, Chaz recalls: "That was my first death threat.
"I was expecting a backlash from Dancing With The Stars. It was certainly more than I expected.
"I've been dealing with the conservative religious right here for years so it's really par for the course.
"Thankfully, nothing serious happened after the threats but I was cautious about security."
Born in 1969, Chaz enjoyed a privileged upbringing. But he always knew he was different and his teenage years were troubled and angst-ridden.
His flamboyant pop star mum might be a gay icon but Cher initially flipped when Chastity revealed she was a lesbian.
Further down the line the pair also had to work hard at their new relationship as mother and son.
Chaz recalls: "As far back as four or five I felt like a boy and wished I was a boy. At that time I didn't know anything about people being transgender or changing their sex.
"As I started to get older I made the mistake of thinking I was gay. "My mother is a gay icon yet she wasn't over the moon when I came out as a lesbian in 1995. I wasn't surprised by her reaction. In fact, I knew it was going to be bad."
Cher had begun to accept that her daughter was a lesbian when she was hit by another revelation.
In 2009, Chastity announced she was having surgery to become a man.
Chaz says: "It took me a long time, into my early thirties, before I really figured out I was trans- gender. Then it took almost ten years to get the courage to transition because I was Cher's child - everyone was going to know about it.
"Three years ago I had my breasts removed. I give myself a daily shot of testosterone.
"To begin with there were changes every day - my skin, my body hair.
"I've waited half my life for body hair and now I've got back hair.
"It has been difficult for my mother but I respect that.
"For parents this could be something that's kind of hard to deal with.
"It's a process of grieving for a child you've lost and adjusting to the new one taking their place.
"It takes a lot of time. Mom loves girlie stuff so it was difficult because I was never that person. I could never give her that experience.
"As it goes on I think she feels more comfortable with me as Chaz.
"If I'm taking flak in the Press or people are being mean on Twitter, Cher will jump to my defence.
"She sticks up for me - and what an ally to have. We are developing a new relationship."
Far from brushing over the more difficult aspects of his troubled past, which included an addiction to prescription medication, Chaz is remarkably frank.
Looking back, he reckons his gender issues worsened the problem and had an impact on his behaviour. He admits: "I had a dependency on prescription drugs. I'm as open as I can be about it. The substance abuse was definitely a part of what I was going through.
"I was trying to escape my feelings and pain. All I cared about was being high.
"I've been sober now for more than eight years. I still go to 12-step meetings.
"If I hadn't done that and dealt with my issues I wouldn't have been able to live the life I have today.
"I'm extremely grateful for how things have turned out.
"Since transitioning, my life has been really amazing and so many of the problems and worries have gone away."
Celebrity male to female transsexuals include Big Brother 2004 winner Nadia Almada and actor Alexis Arquette - but Chaz is the only well-known female to male.
Another case is the eldest child of Hollywood stars Warren Beatty and Annette Bening.