Speaking at the press conference in San Sebastian, Garrel said he didn't want his film to be easily defined in terms of genre. He outlined the way that he and Carrière worked together. "It was a dream for me to work with Jean-Claude since I was 16," he says. "Of course, because I'm French and as I am, I wanted to make films about men and women. I talked to Jean-Claude and then I realised that we could be a good couple. That's because he has his age and I have got my age and sometimes, for example, I'm much more sentimental than him. Jean-Claude is very dry and rough and tough.
"He hates, for example, melodrama and I love melodrama, so we had conflict sometimes when we were building the script. I was shaking because I admire Jean-Claude so much."
"He's an very sentimental man," Jean-Claude interjects.
Garrel says that Carrière was happy to put a pen through anything too soppy, so that much of the comedy in the film comes from the matter of fact way that 'bombshell' information such as pregnancy is presented.
"We created a new person with the mix... maybe it's a woman," he says, before adding, "Do you get my joke? It's a French joke. We built a bridge and maybe that bridge is a woman. I hope so."
Carrière adds: "We had to forget about our differences, because he's 35 and I turned 87 the day before yesterday. What he didn't say is that I worked with his father before working with him and that also is a way of getting closer together.
"I don't know how to say this, but to work in three generations. Louis is a very talented man, very good looking and he's a decent actor and a very faithful friend and I love him very much. We worked, trying to forget our difference in age, and that's very difficult because one of us is eightysomething and the other is thirtysomething.
"I started in films before Bunuel with Jacques Tati and Pierre Etaix and Pierre Etaix was the main actor in our films. And working with the main actor, who is also going to be the director helps a lot because you already see the first version or the first image. The actor is the director but he's also your collaborator so that gave me the occasion of going back to my beginnings.
"Another interesting thing is that it all worked. Both of us got along very well, because if we didn't, it would have been a disaster."
Asked about the film's brisk 75-minute runtime, Carrière added: "I'm not trying to redo a film that I've already written before. I've written over 100 screenplays and I have never used a voice-over - and here there are three people who have a voice-over. It was something completely new to me and if you reflect on it, it belongs to the language of cinema. It doesn't belong to the language of literature or of plays or theatre. It's a weapon of cinema and it's used sometimes in a distant way. So, for me, it was the experience of mixing the three voices of the three characters and seeing what the audience sees, the mistakes they make and the lies they tell. All of that interested me - and I'd never done that before."
Garrel said he was very proud of shooting the film in four weeks - or at least he was until he found out in interviews that Luis Bunuel shot his greatest films in 18 days, "so my proudness was a little bit lower". He adds: "Then Anna Karina told me that Jean-Luc Godard made Vivre Sa Vie - which is a masterpiece - in 11 days, so now I'm less proud to say I shot in four weeks."
He says that his theatre background means that he views "boredom" as "evil", adding: "The 75 minutes was made for this."