Ryan Murphy was "shocked" at how emotional he was working on The Shards.

The TV mogul has teamed up with Bret Easton Ellis for a small screen adaptation of the latter's semi-autobiographical novel, which follows his life as a 17-year-old as its turned upside down when a serial killer sets their sights on his prep school.

The Shards also tackles the HIV/AIDS epidemic, with the subject matter leaving Ryan "emotional" .

He said: "I was shocked at how emotional I was. I was shocked. So many times we'd be shooting it, and there would be a song or a moment, and I would get really emotional and leave the set,

"I cried. I cried, not just because it was my childhood, but because 1981 -- I was 16, and I had my first date in February.

"hen three months later, in July of that year, the New York Times wrote about a new disease hunting young people called AIDS.

"I lost a lot of friends who did not get to grow up -- knock on wood -- like I did, and so I had a lot of gratitude that I survived that period."

Ryan added that he had to make the decision to go back to therapy once The Shards "unearthed" some memories that had left him traumatised.

He told The Wrap: "It was very emotional for me, the early '80s. Of course, this show was set before people really talked about [the HIV/AIDS epidemic]. But it was always present in my mind. It was always a subtext in the work.

"I talked to the cast a lot about it. We had many dinners, and they got to hear about my crazy childhood.

"I thought I had dealt with it, and I had not. I had a lot of PTSD. I started seeing a shrink again. Like [making 'The Shards'] unearthed a lot of joyous and hard feelings, and but it was fun to make at the same time. So it was kind of a mindf***."

Ryan said the situation was made even more emotional by the fact that he's a parent now too.

He mused: "I've never really done something about my childhood, which was interesting and fraught and cool. I was like, 'Oh, that's interesting. I had my first kiss. I failed my first driver's license. I went to my first dance'.

"So I got to do all that stuff and revisit it as an adult with three children of my own."