Stephen Graham suffers from imposter syndrome.
The 46-year-old actor has said he struggles with the psychological pattern - in which a person doubts their accomplishments and believes they are a fraud - as he often thinks he doesn't deserve the success he's had because of his "working class mentality".
He said: "If I'm being really honest, it's kind of happened maybe over the past year, that kind of imposter syndrome. Where you think to yourself, 'Hang on, this is all going to go away any minute now'. That working class mentality that sometimes you can suffer from of like, 'F***ing hell, I don't really deserve this'.
"And it's like, 'No, you've worked your a**e off, you've put your blood sweat and tears into this.' You've earned it. You've really earned it, and you truly appreciate it.
"But for me, I would say that kind of imposter syndrome has only kind of left me a little bit over this last year of my life, at 46."
Stephen particularly struggled with the syndrome when he was filming 'The Irishman' - which was directed by Martin Scorsese - alongside Hollywood stars including Al Pacino and Robert De Niro, and said his wife Hannah Walters had to remind him of his achievements.
"The morning of [our shoot] I phoned Hannah and I was f***ing s***ting myself. I was like, 'Love, I don't know if I can do this'. And she was like, 'What do you mean?' I was like 'Love, it's Al Pacino. Hannah, it's Al f***ing Pacino. I've gotta go and do a scene with Al Pacino.'
"She went 'Yeah, but you know what you wanna do. Stop it. You deserve to be there, you've earned the right to be there. Martin wanted you there, he's not doing it as a favour, you got there on merit. It's your hard work and what you've put into your career, and how he knows you can act. That's why he wants you there.' "
And although the 'Boardwalk Empire' star sometimes grapples with the idea of his own success, he wants to help others land their dream career through a production company he has recently launched with his wife.
Speaking on the 'Pound for Pound' podcast, he said: "We've set up a production company, me and the missus, and I kind of want to get involved in aspects ... I'm not saying directing or anything like that, but our aim with the production company is we want to try and give people opportunities. Like writers and directors, and I think that's what's needed. I think we need to spend a little bit more time and a little bit more care and dedication on young people who want to be not just actors, but writers and directors."