The singer, 35, won the ITV competition in 2012 and has gone on to have a hugely successful career.
Clips from his time on the programme were played and, when asked what it was like to watch them, Arthur confessed: “It’s a little bit triggering to be honest.
“That was probably the best and worst experience of my life, because it was just an absolute pressure pot, so a lot of anxiety came with that whole thing and certainly in the immediate aftermath of X Factor I struggled quite a bit.
“So, when I see that I think, what an amazing thing, I got that platform to showcase my abilities as a musician and it has allowed me this incredible career.
"But also, it was quite a traumatic time as well.”
The Impossible singer – who has been open about his mental health struggles – added that he was “genuinely plucked from obscurity” and wasn’t really prepared for fame.
Arthur recently became a dad, welcoming daughter Emily with partner Jessica last year.
Discussing fatherhood, he said it “has given me a completely different perspective”.
“I’m a bit of a softie now, look at life completely differently,” he said. “She has changed me.”
The star said it had also had an impact on his music as when he's writing about love, Emily is “at the forefront” of his mind.
“I think about her more than anything else… so she has become a real inspiration for me,” he said.
Watch: James Arthur feels "very grounded" since becoming a dad