Much discussion has rested on the film’s main performances by Philip Seymour Hoffman and Joaquin Phoenix, who plays his unhinged protege. Both actors split the top acting award at the Venice Film Festival, where the film debuted.

Hoffman dispelled suggestions that his character of Lancaster Dodd was purely based on Scientology founder L. Ron Hubbard and discussed the broader themes of the film.

You seem to just roll from one great role to the next.

Yes, it’s going awful, I mean, Paul Thomas Anderson ... giving me these opportunities. I just can’t bear it.

How did you create your character, Lancaster, and who did you base him on?

Ultimately it was just knowing what we didn’t want to do. I think most people have been interested about the Scientology and L. Ron Hubbard stuff, and the thing is Paul used that stuff to have a venue to write the story. And a lot of our discussions early on were like, ‘I don’t want to play L. Ron Hubbard because that would be very distracting because that is not the movie.’ So a lot of the choices had to do with how not to be L. Ron Hubbard.

It is pretty clear we made choices to make sure that the way I behave, the way I talk, it is all very different from L. Ron Hubbard. Ultimately it was about creating a unique person that was a piece of fiction.

Perhaps fuelling that fascination were mysteries about Scientology to begin with?

That’s a worthy discussion, that is a worthy article to write. People’s feelings and what Scientology brings up for people and how would you compare that to other movements of that time and how would you compare that to religion or Catholicism? That is very interesting because to me this guy is the head of anything you want him to be. You know what I mean?

We always talked about this film being a life-changing moment for both of them, and things happen in your life to change your life. After they happen you think, ‘Did that actually happen? Did I actually go through that?’ Something that is so profound is sometimes so elusive and so hard to nail down. And it becomes a memory and an anecdote and some weird dream.

People are fascinated by broader themes of what this film is about. What are your thoughts?

It is about an intense emotional connection between two men and how they both need each other, and are both the mirror opposite but ultimately very much alike. So I think all that is very specific and clear in the movie and it creates a strong emotional attachment that both of them are scared to walk away from for fear of finding out they are nothing without the other person.

I think that is what the movie is getting at. And then what happens, that Paul does so brilliantly - that he doesn’t do in such a simple, banal or obvious way - is he brings in that time period, post-World War Two. He brings in a movement that is somewhat like Scientology, that time-warp kind of movement ... It is about all those things and how they feed into the core thing, which is this relationship.

People also seem focused on the scene where your character sings to Joaquin Phoenix. Can you shed light on that?

I think it is beautiful. It is about intimacy and obsession and wanting to control somebody, because you are so scared to lose them. Anyone who has been in love before understands that.

Was it difficult to establish your own presence opposite Phoenix?

It’s not an everyday occurrence, no, but when I see it I am happy because it makes my job easier. He (Phoenix) is actually playing the part, which is a guy who is obviously severely damaged.

Lancaster isn’t a walk in the park either. He is a bull in a China shop too. There are a lot of similarities between them if you look hard enough. But they are both pretty volatile guys, but one realises he wants to control it and the other one can’t.

What do the Oscars mean to you now that you have one?

I think it is important to respect the attention that gets brought to something that everyone worked really hard on.

Talking about respect, actors like Meryl Streep sometimes joke about actors’ current high stature. What do you think?

No one wants to be pretentious about what they do or take it seriously, because that is just weird. But I think, too, you have to respect it and to realise where it can take you and what power it can have, I think is important. But that is true of anything.

Salman Rushdie said recently that movie stars have replaced writers since the ‘50s in terms of their influence.

I do feel that there are some really smart people, who are doing that, who are actors. And I think they do it well, I don’t judge that so much.