The Lost star plays genius scientist Simon in the new science fiction series FlashForward, who he describes as "a little OCD".
Dominic revealed playing an oddball hasn't been hard, but added: "Although I've done a few things, playing around with the OCD thing - when I leave my house I do a few things just to see what that's like."
He added: "It's fun - you just have to maintain a real level of stillness. There's an air of confidence that comes through that stillness which dictates on the character so it's been a fun ride."
The 32-year-old British star revealed he always loved acting and wanted to ask his parents for an agent for his birthday as a child.
He said: "I knew that I wanted to act when I was about nine or ten. I remember thinking that I wanted to ask my mum and dad for an agent when I was 13 for my birthday, but I chickened out - I probably asked for a Scalextrics instead. but yeah, I always wanted to act."
:: FlashForward, co-starring Jack Davenport and Joseph Fiennes is on Five on Mondays at 9pm.