Jamie Wallis was praised for his bravery after revealing that he is are “not OK”, and for being open about having gender dysphoria.
The Bridgend MP said: “I have never lived my truth and I’m not sure how”, but “perhaps it starts with telling everyone”.
The message was posted online shortly before 3am, following a gathering for Tory MPs at which Boris Johnson reportedly made a joke about trans issues.
Mr Johnson responded to Mr Wallis’ statement by saying: “Sharing this very intimate story would have taken an immense amount of courage.”
He said the story would “undoubtedly support others” and “the Conservative Party I lead will always give you, and everyone else, the love and support you need to be yourself”.
In his statement, Mr Wallis said: “I’m trans. Or to be more accurate, I want to be.
“I’ve been diagnosed with gender dysphoria and I’ve felt this way since I was a very young child. I had no intention of ever sharing this with you. I always imagined I would leave politics well before I ever said this out loud.
“There was a close call in April 2020 when someone blackmailed me, outed me to my father and sent photographs to other family members.
“He wanted £50,000 to keep quiet. The police were so supportive, so understanding and on this occasion the system worked.”
The MP said the offender was sentenced to two years and nine months in prison after admitting his guilt.
“For a while it seemed as though I would be able to get on with things and move on,” Mr Wallis wrote.
“Being an MP and hiding something like this was always going to be tough, but I arrogantly assumed I was up for it.
“Well, I’m not.”
Giving details of the rape, the MP said: “I ‘hooked up’ with someone who I met online and when I chose to say ‘no’ on the basis that he wouldn’t wear a condom he chose to rape me.
“I have not been myself since this incident and I don’t think I will ever recover. It is not something you ever forget, and it is not something you ever move on from.
“Since then things have really taken a tumble. I am not ok.”
The MP was arrested and subsequently fined over a car crash last year.
Mr Wallis said he fled the scene following the crash in November “because I was terrified”.
“I have PTSD (post-traumatic stress disorder) and I honestly have no idea what I was doing except I was overcome by an overwhelming sense of fear.”
The personal statement came following the night out for Tory MPs, at which “I was reminded of the incredible support those you work with can provide”.
“I’ve had a lot of support from the Whips since I was elected,” the MP said.
“Not for the reasons you might think, but there’s a lot that goes on in MPs’ lives and the Whips play an important wellbeing role – as far as I’ve seen they try their best to support and help MPs who are having a tough time. Well they’ve certainly earned their keep with me.”
Conservative MPs had gathered at the Park Plaza hotel in London, just across Westminster Bridge from the House of Commons.
At the dinner, the Prime Minister reportedly said: “Good evening ladies and gentleman, or as Keir Starmer would put it, people who are assigned female or male at birth.”
The row over trans rights has been a key battle in so-called culture wars between the parties.
Tory party chairman Oliver Dowden said: “Proud of my colleague Jamie Wallis.
“As a Conservative family we stand together, and we will support you.
“I hope that your brave statement will help others.”
Fellow Tory MPs also showed their support for Mr Wallis, with former whip Mike Fabricant saying it was “a very brave statement”.
Alicia Kearns said: “You have changed this country today Your bravery will give hope and courage to people across our country.
“From the trans community, to survivors we all here for you, as you live your life as your true self, but ever as our friend.”