I grew up in a small town in Ireland and didn't know any actors. I never thought it was a viable job. It wasn't until I was on 'The Tudors' that I realised it was a possibility.

It's not an understatement to say that I owe everything as an actor to 'Merlin.' It was pretty much my first job, and I didn't know what I was doing for many years on it. It wasn't until the third and fourth series - the fourth series especially - that I really found my feet with the character, and as an actress.

I had this vague notion that one day I might be editor of 'Vogue China.' It was a bizarre ambition, as I didn't speak a word of Chinese. There were flaws in my plan, admittedly.

I'm a very ambitious girl. I'll go wherever there is a good part.

Hank Paulson, obviously, had spent his career on Wall Street, had a deep knowledge of the Street, and also was a very forceful personality, had a very good relationship with the president, and was in a very different place, for example, than Ben Bernanke, who is an academic, quiet guy: spent most of his time thinking about monetary policy.

As an artist, you can always learn different ways to refine your look. I mean, you look at any one time in my career and you see all the hairstyles I went through. You make changes until something feels comfortable with you. And people vibe with it because they can see the difference.

As an economist specializing in the global economy, international trade and debt, I have spent most of my career helping others make big decisions - prime ministers, presidents and chief executives - and so I'm all too aware of the risks and dangers of poor choices in the public as well as the private sphere.

Acting is something I've done since I was in high school, but I never had a model in my life, whether it was a mentor or a parent, where I could realize that acting could actually be a career.