WATCH: Netflix’s Heartstopper star makes his Chichester debut

And with perfect timing, the production comes hot on the heels of the announcement that the second series of Heartstopper will be screened this August. 4000 Miles is also Sebastian's first time on the stage in eight years. The last time was in Trevor Nunn's King John when he was 13 years old.

“I had wanted to see this play when it was being done with Timothée Chalamet at the Old Vic just before Covid but it was cancelled and I guess because of scheduling it then got cancelled altogether but I had actually booked to go a couple of times I was so excited about seeing the play with these two amazing actors together (Chalamet alongside Dame Eileen Atkins who now stars in the Chichester production).” Now, almost incredibly, Sebastian is actually in it: “I just can't believe it really. It was just not something on my agenda but when I heard that it was coming back it just seemed like a dream to be performing with Eileen Atkins and to be directed by Richard Eyre. It's been just such a wonderful experience. They are both so good at what they do but they're also both so kind and generous and so supportive towards us, the younger ones coming in and collaborating with us. There's no sense of ego at all. They are just so warm and welcoming. It should have been terrifying but it completely isn't. There's just such generosity and they're both such lovely people. I met with Eileen a few times before rehearsals started and we ran through some lines together. Having that time together we got to know each other which was really useful and that made it perhaps one per cent less terrifying than it would have been when we started rehearsals!

“I am playing Leo in the play who arrives having cycled 4,000 miles and arrives at his grandmother's apartment in New York and he stays for three weeks. We've got these two people who are both refusing to move on and refusing to change. They are living together and helping each other to understand the loss that they have both had in their lives but it is a really gentle play about loss. It unfolds so gently. There's no big twist. It's a play really about setting these characters in this situation as we learn more and more about them.”

Sebastian comes to it on the back of the huge success of the first series of Heartstopper and with the second series to be released this summer: “It has been massive. It was one of those shows where you just didn't really know how it was going to go but it has proved so uplifting and so joyous for people, especially for people who have been starved of queer stories. It is actually quite unique in that it is such a sweet and simple young love story that happens to be queer love but it is such an infectious show you just can't help but fall under its spell.”