Have you always been a fan of Annie?
My mum tells me it was the first musical she took me to. That explains why I had a record of it that I played every day after school. It was probably the first theatrical experience I had, so it feels very fitting that my West End debut is doing the show that introduced me to theatre. I saw the 1982 film later, with the wonderful, indomitable Carol Burnett and fell in love with it all over again.

What appeals to you about playing Miss Hannigan?
Simply, she's a beautiful comic-tragic part. She's kind of got everything to play. Anger, volatility, sadness, vulnerability and always has wonderful opportunities to go for laughs too. I love her!

You're making your West End debut, are you feeling nervous?
Very nervous, yes - thanks for reminding me! It's a wonderful company and I feel so safe in the hands of Nikolai Foster and his team, but there are the inevitable debut nerves. To be a part of our rich West End tradition is amazing but carries a responsibility.

You mentioned working with director Nikolai Foster, how has it been with him in rehearsals?
I really couldn't feel luckier to be working with Nikolai. The first time I met him I connected with him and it was clear we were on the same page about how we felt about theatre, musicals, and indeed Annie in particular. He is a dream to work with. He has the cheekiest little laugh!

You're coming back to the stage after lots of TV work, have you missed it?
My sitcom is performed in front of a live audience, the process has a lot of theatrical crossovers, and I then did a stand-up tour, so I have always remained connected to my first love of performing with an audience. Nothing beats that immediacy, particularly in comedy. But to be doing theatre proper, as it were, with an ensemble cast and having the chance to hone and develop it night after night, rather than just the one studio sitcom recording is very exciting.

They say never work with children and animals, but you're diving in at the deep end with the kids. How has it been?
Much better than I might have feared! I don't have any scenes with our lovely dog sadly, but lots with the kids and they are all great. Such energy and sparkle but also very focused and well behaved. And it's fascinating watching their bravery at that age. They just get on and do it. It's a good reminder to let go of all the inner chatter us adults have and just boldly go for it.

You're not known as a singer, did you have to do much vocal preparation ahead of rehearsals?
Yes, hold on to your hats London, I am singing for the first time. I played the piano when I was younger, so I am musical and could always hold a tune, but enjoying the odd harmony at a carol concert is very different to what you have to prepare for when reaching a large West End theatre. I've worked hard to learn new skills necessary to sing, I knew it would be quite a challenge but the musical director assured me, before I had signed on the dotted line to do the part, that he thought I could get there. So blame him if it all goes t*ts up! I am now really enjoying it, especially as it's all about singing in character, so hopefully all will be okay. (Excuse me whilst I just crawl in to a little worried ball on the sofa…)

What's the funniest story to come from the rehearsal room so far?
Oh there have been so many laughs. But it's one of those annoying things when they are all "you really had to be there" moments. I think that's why I was so looking forward to do a theatre job with a big company because you become a family and there are instantly lots of in-jokes that only that unique group of people at that time will know about. So yeah, what happens in the Annie rehearsal room, stays in the Annie rehearsal room…

What is your favourite moment in the show?
Oooh, quite hard to pick. It's not a secret that I picked "Easy Street" from Annie as one of my Desert Island Discs so singing that is always great. It's a fantastic number. There's a few Hannigan comic moments I have loved doing every time in rehearsal that I hope the audience like too, but I won't ruin them by sharing now. Such a tease.

Sarah Hadland and Miranda Hart attend press night for Miss Saigon in 2014
Sarah Hadland and Miranda Hart attend press night for Miss Saigon in 2014
© Dan Wooller for WhatsOnStage

Have you always wanted to become an actor/comedian?
Yes, since I can remember really. I fell in love with Eric Morecambe and wanted to be a comedian. Comedy will always be my first love. I think it's such a vital art – where would we be without laughter. But actors such as Juliet Stevenson, Imelda Staunton, Emma Thompson, Julie Walters (I could go on) inspired me as I got older to want to do more drama and tell stories in a different way without necessarily going for the laughs.

If you hadn't become an actor, what might you have done professionally?
My other two loves are sport and animals. So hopefully I would have done something in one of those areas. The dream was always to be a professional tennis player. I think I have to accept that ship has sailed.

What's the best advice you've ever been given?
I can never think of any singular piece of advice from one person that ever stuck with me. But I have lots of mantras and sayings and pieces of literature that are important to me. The one I am using a lot at the moment is "this too shall pass". It's so easy to think the difficult moment you are in will never change, but everything changes, everything passes, new feelings emerge.

What was your worst ever audition?
My inroads into acting involved a very small amount of auditioning strangely. I started to get work on the comedy circuit via casting directors who had seen my shows at the Edinburgh Festival, or friends who I had done sketches with. So I am very lucky not to have any horrific audition stories.

Who are your idols?
In terms of inspiring me in the arts, number one would always be Eric Morecambe. But I also think the following women are pretty blooming cool: Meryl Streep, Ellen, Allison Janney, Joyce Grenfell and Victoria Wood. I could give you a long list actually.

What do you enjoy most about acting?
If I had to pick one single thing about acting I would say it's about the effect it has on people. Hopefully positive! But what people take away from the work I do. And I hope with Annie they've had a blast of an evening, had some laughs, perhaps a little weep and come out feeling more hopeful and joyful than when they came in.

And least?
The costumes. I know – strange answer. Although they are of course a key part of the character and of performing, I always end up feeling uncomfortable or hot, or it's just not what I feel like wearing that day.

How do you unwind?
Film and TV is always my go to for relaxation. So on the way home I will think of what I feel like watching, get in, put my PJs on immediately and then it's straight to the sofa, cup of tea and some gripping or relaxing watching to escape. Currently it's a heady mix of Star Wars (courtesy of our choreographer Nick Winston) and Line of Duty.

How do you prepare for performances/rehearsals?
I like to learn all the lines before the first day of rehearsals and feel warmed up. So I always do some prep at home before rehearsals every morning. That's particularly the case in comedy. The more precise you can be the better the laughs. In terms of the performances, I just try and keep as relaxed as possible in the day, make sure I eat the right food to sustain me for a long performance and listen to the audience as they start to come in – that then gives me the adrenaline I need to think about why I am doing what I am doing, and start to focus on the character I am getting into.

If you could swap places with anyone for a day, who would it be?
Blimey. Ummm. I'll go with Andy Murray. I want to know what it feels like to play on Centre Court at Wimbledon and how the nerves of playing a tennis match compare with that of stand-up or theatre.

What's next for you after Annie?
I have a children's book coming out in the autumn which I am really excited about – the last few years have mainly been about writing for me. But that means I am feeling ready to keep treading the boards or do more TV and film. There is one definite thing – but that's still a secret – and other than that, it's often a myth that the scripts roll in, so if someone wants to give me an acting job – HELLO!

Click here to buy tickets for Annie

Annie will run at the Piccadilly Theatre from 5 June 2017 to 6 January 2018, with previews from 23 May.