High budget, competition-centred, talent show reality TV may be gaudy and formulaic but it can also bring people like Jessie Buckley into the public consciousness. Originally from Ireland, the eldest of five kids, Jessie, who came second in 2008’s I’d Do Anything, went on to study at RADA and spent her first summer as a graduate playing Miranda in TheTempest at The Globe Theatre. She’s played Anne Egerman in the Trevor Nunn-directed production of A Little Night Music in the West End and is now treading the boards as Princess Katherine in Michael Grandage’s take on Henry V opposite Jude Law.

Henry V sees young Prince Harry all grown up and ruler of his own land. Now a valiant King, he leads his army in the conquest of France where Princess Katherine is to be part of his prize.

We met up with Jessie her in the final week of rehearsals to chat about Princess Diana, working with the heavyweights and attempting to learn French.

Hey, how’s your day going?
Great! I managed to sort out some house stuff! That sounds rubbish but normal life gets completely put on hold during rehearsals so when you managed to tackle something like sorting out the washing machine it’s kind of brilliant.

You’re playing a princess, how ornate is your costume and how do you feel in it?
We get to have a week in costume before we go into the theatre which is such a luxury. For me the shoes of the character are always something really important. So I’ve had my shoes in from the beginning of rehearsals. They’re wedges thank goodness so I can actually walk in them. Maybe I’ll do something ker-azy and flash a foot! And of course when you’re got a crown on you feel tres posh!

In the play, Katherine is learning English and speaks with a heavy French accent, is she a bit of comic relief?
She’s a mixture between innocence and a girl coming of age. She’s taking ownership of her potential power as a woman in the role that she’s about to move into. I could never just play her for laughs. For me, every character that I take on is another human person and you just kind of slip into their skin for a few months. There’s a lightness about her because of where she is in her life but they’re not slapstick, no zut alors!!

How are you getting to grips with the French?
My whole first scene is completely in French and I really love it! I’ve always wanted to learn another language and I’ve just been watching loads of interviews with Marian Cottilard. I met a woman in Brixton the other day, she was a French waitress in a cafe and I kind of roped her into a language exchange. So I’ve been learning little bits of French, just for shits and giggles.

Tell us a bit about the relationship between Henry and Katherine, he’s a lot older than her, does he have all the power?
They are such beautifully written scenes and so delicately integrated. There’s such a big journey that takes place between these two characters in such a short space of time. Even though he’s very powerful and he’s conquered her land, it is her turf that he’s on. She holds a massive trump card in that she is the political pawn which is going to unite these two countries into some sort of peace and knowing that, she doesn’t back down from playing a game with him. The key scene between them begins as a game and unravels into something that sees them shed their royalty and they end up as two very human people who kind of fall in love with each other.

Is it hard to figure out Katherine’s motivation, what do you think she really wants?
She wants to be loved and she wants to love. She wants ownership of her own power in order to be included in the power games of this play. From the first scene with Alice, she makes an important decision not to be just an aesthetic political pawn but to be an intellectual one. She’s learning English not just to impress people but to be able to communicate with somebody from a different country with a different language. With Henry though, she’s got that childish dream of escaping into something loving or perhaps into another country. She makes me think of Princess Diana.

Diana, really?
Yeah! I watched a lot of interviews of Diana before her wedding to prepare for this part in a way, because that was such a high profile wedding. She fulfilled an aesthetic thing that society seemed to have about what that union would mean and how beautiful and wonderful it would be. You can see it in interviews with her and Charles. She kind of dreams of stepping into this fairytale with becoming the future Queen of England and her own family was quite broken and she was quite vulnerable as a person. I think she was so desperate for it to be a marriage of love too. Whereas if you look at Charles – and of course this is just my opinion – he seemed to look at it more like a duty. So she became quite isolated and took ownership by becoming a very powerful political woman and acknowledging that she wanted more than just her marriage.

It’s like in this play the women are on the periphery of war. When you know something like war is going on around you, you want some agency over it.

You played Miranda in the Tempest previously, is it worth comparing Miranda and Katherine?
Their energy is very different. Miranda is this earthy firecracker of a girl and what’s interesting about her is that she has no social conformities to navigate because she’s been living with her father on this island for so long. So when she falls in love she just blurts out what she feels. Whereas with Katherine, she’s been told from infancy that she has to behave in a certain way, talk in a certain way, think in a certain way.

If you met Katherine in a bar, what would you think of her?
We’d get along. You have to like a character you’re playing. I’d probably be quite nervous of her. I get quite nervous of people who have done so much more than me. I’d probably give her a weird hug and then think for the next few days about how awkward and embarrassing I was.

That brings us nicely to the inevitable question: what’s it like working with Jude Law?
Of course before I started rehearsals I was apprehensive about working with a big star but do you know what? He’s genuinely lovely and he’s a proper lad. From day one he was a leader and playing a part like Henry, you have to have that. But even with the scenes with me, he never second guesses himself and yet he’s open to discussing all things that might or might not work and having a great dialogue with Michael (Grandage). Very often you can mistrust yourself at the beginning of a rehearsal process and it can sometimes take a long time to get out of that but he’s a really lovely guy and there were none of those difficulties.