Marcelo Dos Santos speaks about his new play Backstairs Billy, now open in the West End

Written by Marcelo Dos Santos, Backstairs Billy is a touching new play directed by Tony and Olivier award-winning director Michael Grandage. Starring Penelope Wilton (Downton Abbey, Ever Decreasing Circles) and Luke Evans (Beauty And The Beast, Nine Perfect Strangers), Backstairs Billy tells the extraordinary tale of The Queen Mother and her most loyal servant. Here, Marcelo tells us more about the production...

This is your first West End production. Tell us about the play?

Backstairs Billy is a comedy about the unlikely friendship between The Queen Mother played by Penelope Wilton, her infamous butler William (Billy) Tallon, played by Luke Evans, and the elaborate and frankly camp "court" they created at Clarence House. Set in 1979 just before the Winter of Discontent, it blends high comedy with human drama, pathos as well as politics.

What was the appeal about writing about the Queen Mother?

I was primarily drawn really to the dynamic between the Queen Mother and Billy. They were together for 50 years and their relationship weathered a number of scandals and I wanted to explore what drew the working-class Billy into that orbit and what the ties were that kept binding them to each other. It felt like a really interesting way of exploring quite big issues like class but in a playful and engaging form with the potential for a lot of farce and fun along the way.

Have you been involved in the rehearsal process?

Yes, I've been in the initial first week of rehearsal and will now pop in and out. At a certain point it's useful for the writer to get out of the way.

You won last year's Fringe First award at Edinburgh - what was that like? And tell us about the award-winning show?

That was amazing. The whole thing was a ride. The show is called Feeling Afraid As If Something Terrible Is Going To Happen and it was produced by Francesca Moody, who produced the original productions of Fleabag so we knew we were in good hands, but it's almost immediate success was just lovely.

It's a one man show starring Samuel Barnett (History Boys, Dirk Gently) about a self-deprecating, permanently single gay comedian who finally meets his Mr Right and then does everything wrong. And there's lots of twists which I won't give away. The show is coming to the Bush Theatre in London this November and December as well, so it's a busy Autumn.

What are you working on next?

I'm currently working on a BBC drama commission and a couple of other things I probably shouldn't talk about yet.

What drew you to become a playwright?

I've always loved the theatre and it's one of the most collaborative mediums. I'm not very good at just sitting on my own in a room, which is a problem for a writer. But with theatre you get to be part of a company and create something together which is both tangible but also ephemeral because it's primarily about the live experience.

What does a working day look like for you?

A lot of procrastinating unfortunately but I'm trying to develop better routines. I try and get up early, go to my workspace, go to the gym and then eat chocolate the rest of the day, because... balance.