Delia Ephron is wearing black. Black trousers and a black T-shirt. "I was probably wearing the same yesterday," she says. Like the other Ephrons in her family, including her late, famous older sister Nora, the creator of When Harry Met Sally, Delia is a writer. Her work includes novels, essays, screenplays and a play called Love, Loss and What I Wore which, like the rom-com You've Got Mail, Delia wrote with Nora.
"There's an ode to black in the play," says Ephron about the work, which is being performed in the UK for the first time at The Mill at Sonning Theatre in Berkshire. "Black looks better on you than any other colour. That's what Nora and I always thought. When women started colouring their hair, which they all do in New York, black clothes looked best for them. The women who age with grey hair wear colours."
If there is such a thing, Love, Loss and What I Wore is a play for women. Based on Ilene Beckerman's best-selling memoir, it connects clothes to experience in a way that men are just not, on the whole, able to.
"One of the amazing things was that there was nothing about Beckerman's life that had anything to do with our lives," says Ephron. "But, the minute you read it, you think about all the clothes you wore, and what happened to you when… the boyfriends, the break-ups. Everything in your life comes back to you via your clothes. And we realised the stories on stage would start to trigger the audiences' memories and that we would have a very powerful piece of theatre."
Ephron suggests that "with men, it's music. They have a soundtrack to their lives. Women do, too, by the way. But they also have clothes."
This is a very Ephron thing to say, the kind of astute observation about gender difference that could happily exist in When Harry Met Sally, or even in Nora's Heartburn, the book based on her marriage to, and divorce from, Washington Post journalist Carl Bernstein. In fact, it would not be a surprise to Delia if her lines were in those works.
For the Ephrons, a good line is to be used and it never much mattered which sister came up with it.
Writing the play, which involved soliciting stories from their friends, was a long process. Nora and Delia optioned the book in 1996 but the play didn't open in New York until 2009. It must be a bitter-sweet experience to see it revived. The death of a writing partner is a heavy loss for any author, much more so if that partner is also a sister. "I have only the most wonderful feelings about it," Ephron says. "It was the most smooth collaboration between us."
The sibling relationship did not change over the years. But the writing relationship did. "In the beginning when we did our first movie together, This Is My Life [1992], Nora was in New York and I was in Los Angeles.
"We would get together and do everything. We would sit in the kitchen and outline the story, eat a lot, sometimes shop and then we might go home and send each other scenes with problems for the other one to solve. That's one of the great things about collaboration. You can always just bump a problem to the other one. And then I got better as a screenwriter and Nora got much more into directing."
Writing together wasn't always such a smooth process though, even when they were working on eventual hits such as You've Got Mail. Who ruled the roost?
"Is there a more a perfect embodiment of the director/writer relationship than older sister/younger sister?" Ephron asks. "The director is the boss of the movie. So in that sense, yes, there is no question that Nora was the more powerful person. But I also produced the movies with her. And I had such a relentless personality. I never trusted that she would do what I wanted and I would literally just browbeat her into it.
"If I thought she wasn't going to film a scene in the way I wanted, I would just keep at it. She would tell you that I drove her absolutely nuts and that I never trusted her. But the great thing is, if you're sisters, there is always a great feeling. We were very close always. And our parents were writers and there are four sisters [Amy and Hallie are also novelists]. We're all writers and the writer's gene is the most powerful gene in the family."
The sisters' mother, Phoebe, was a driven screenwriter who, with husband Henry, wrote films for Hollywood. She gave Nora a writerly dictum that the eldest daughter always held dear - "take notes". At the time, Phoebe was on her death bed from alcoholism, aged 57.
"We were lox-and-bagel Jews," Ephron says. "Every Sunday, we went to the local deli and ate lox and bagels. We lived in Beverly Hills which was 90 per cent Jewish but I was the only Jewish child in school on Jewish holidays. My mother was against any organised religion.
"She was big pontificator and used to say that religion was the cause of all wars, which wasn't actually true when she said it but it is starting to be now. But we were definitely aware that we were Jews and that we had a great heritage."
As adults, Nora and Delia "borrowed lines from each other the way other sisters borrowed dresses". Sometimes lines were "borrowed" without permission. At Nora's memorial service in New York, which was attended by Hollywood royalty including Steven Spielberg, Bette Midler and Steve Martin, Tom Hanks made a speech in which he quoted a line from his movie Sleepless in Seattle (written and directed by Nora) about falling in love. The line? "It was like coming home."
"Mine," chuckles Delia. "I said it to my husband at our wedding."
According to Ephron, in another speech at the service, Martin Short quoted a Nora Ephron line which only makes sense if you know that hazelnuts are an unfamiliar flavour to most Americans. But "hazelnuts are what's wrong with Europe" brought the house down.
"It got a huge laugh. My husband elbowed me in the ribs and when I got up to talk, which is very difficult when you're so upset, the first thing I said was: 'That line about hazelnuts? It's mine.'"
Ephron's chuckle grows into laughter. "Even in her memorial service, she managed to claim my line as hers. I think there was the feeling that because I was the second sister that she could do that. At least more easily than I could do it to her. It was no accident that we collaborated because she adored me. She just loved everything I said. She thought I was hysterical. And I loved that."