“The first time I ever went to LA, I had just finished doing FM, which was an ITV comedy with Chris O’Dowd. I went for a month, got the lay of the land. I actually went and stayed with Chris, because we’d become friends and he had a room in his apartment. Not being completely on my own had a big bearing on why I took to the place.

It was a February. More than anything it seemed like the right thing to do. I wasn’t following any kind of plan, I was just following that instinct. But it was definitely a conscious decision, with a view to getting an American agent.

I went back later that year and stayed for nine months. In terms of getting an agent, I was lucky. I’d met someone in London – now my manager – who was already aware of me. I had an ‘in’ in that way, she wanted to represent me.

Is it good to be a Brit in Hollywood? If nothing else, it’s a talking point. You come into the room and there’s immediately something different about you that makes you stand out. And they seem to find the accent infinitely adorable. I suppose beyond that, you’ve come from England to work there, which shows a commitment and dedication.

If you are going to work in the US, you do need your American accent to be flawless.

I’ve always loved accents. If I’m telling an anecdote, I give everyone an accent. My American accent was fine, but it was during that initial nine months that it became natural. I could switch between the two without any problem.

As far as visas, there’ll be some no-budget films where you have to sort it out yourself. My first American film was No Strings Attached and part of the deal was they got an immigration lawyer and they put the visa package together. It means you can go freely in and out of the country for two or three years. It’s quite exciting, because you arrive at the airport and they say, ‘Business or pleasure?’ and you say ‘Business’!

I didn’t realise [Elementary] was shot in New York. That was a massive bonus to getting the job; to move to New York for five months. It’s filmed in Long Island and it didn’t hit me until I got to the studio and they were leading me through this warren of corridors. You pass all these different shows and you think what a big undertaking it is.

The main difference between shooting there and in Britain is craft services. In America, they have food at every minute of the day. There’s breakfast, then mid-morning food around 10:30, then lunch and then hot food again around five. And then if they feel like it, they’ll bring in a pizza or churro truck. And then all through the day there’s bagels and sweets and nuts. In England, you get a tray of biscuits and a tea urn. Maybe a slice of melon if you’re lucky.

In my latest movie Man Up, I’m an incredibly irritating optimist. Well-meaning, but cloying. I always envisaged myself doing drama, but I seem to keep booking comedy. It’s an amazing feeling trying to make someone laugh.”

Ophelia Lovibond’s CV

How did she get started? “The first thing I ever did was The Wilsons. I was 12 and turned 13 while I shot it. It was in front of a live studio audience and the main thing I remember is trying not to laugh while David Bradley – who played my dad – was saying his lines.”

She didn’t go to drama school. “I went to the University of Sussex to study English Literature. Because I’d been working on set since I was quite young, I didn’t feel the pull to go to drama school.”

What was the role that changed her life? “I think it was Nowhere Boy. Up until that point, I’d done things that could work around my school work and in the summer. Nowhere Boy was the first film I got after university. I remember filling out the forms and writing actress rather than student and it felt quite a formative moment.

She’s worked with penguins… “It was cold! Really, really cold! They kept the studios at a temperature that was comfortable for them. Me and Jim [Carrey] had to drink hot tea so you wouldn’t be able to see our breath in the cold studio. We had to wear loads of layers and whip them off when they called action.

Don’t ask her if she survived her episode of Casualty. “Did I die? I can’t remember. I don’t think I did. People always mock [soaps], but you learn so quickly. Those shows are really helpful for young actors.”

W1A returns for a seconds series on BBC Two, Thursday 23 April at 9pm.

Man Up is in cinemas from 29 May.