WATCH: Real-life mother and son set to take to the Chichester Festival Theatre stage

Running from Friday, April 28-Saturday, May 20, the piece is set in the roaring 20s in a world in flux. The magnetic Florence Lancaster draws people to her like moths to a flame. But when her son Nicky arrives home from Paris with an unexpected fiancée and a secret, it sets off a chain of events which threatens to pull them all into a maelstrom.

Playing Florence is Lia: “I had been putting off doing any Noel Coward for most of my career because I felt it was excluding. It felt like it was going to be about the upper classes and I just wouldn’t know how to connect with it. I thought that it would all be froth, but actually it was Joshua who said to me ‘Have you read this play The Vortex?’ He said ‘I think it is brilliant.’ He said to me ‘I think we should try it.’ The years passed but we were together with Dan Raggett who is going to direct it and now it is happening. I read it and I just thought it was staggering. It was a play that was Noel Coward’s first big hit in 1924. It was his breakthrough piece and it was an absolute sensation but what really surprised me was that it was actually lacerating about the upper-classes, a wrecking ball to the society after the Spanish flu and after the First World War. It was this extraordinary moment in time when society went nuts. If you had money then everything was possible. It was about living freely and living wildly and being decadent. It was all about privilege in the upper classes, but what fascinated me is that this play is absolutely lacerating towards them. But at the same time what really interested me was this central core in the play between the mother and the son which I found really quite devastating and shocking. It is such a brilliant piece of writing. It was Joshua’s idea to do it. A lot of the people in the business don't know that we are mother and son. We are quite independent in that sense and we're both successful actors in our own right but when he was looking at this it went through his creative head to think ‘Mum would be great casting for this and I think I would be good casting for Nicky.’”

And that real life relationship is definitely something they can use between them on stage “I think it means that we have got an unspoken language between us without ever having to talk about things. We know how to finish each other’s sentences! We have a similar sensibility and similar reading of text. From the start there is so much that is already there and the rest of it is basically trust. You can never take for granted that you can work with somebody. It's never a given and it's the first time we've worked together but it has been amazing. It has also been very moving. There's something that feels effortless. It just feels uncomplicated between us which means that we can create on stage a relationship which feels really complicated.”