As the romantics of the world will attest, it's a sure sign you're in a Richard Curtis film when the tissues come out. This prickling of the tear ducts and overwhelming sense of urgency to rush home to loved ones has been labelled "the Richard Curtis effect" though some people may find his films more sickeningly twee than truly sentimental.
It has earned the British writer-director a reputation as the king of romantic comedies.
Curtis' latest film, About Time, is no exception. In the two screenings I have attended there has been an appreciative sigh from the audience as the credits rolled, followed by a ripple of applause. Then the mobile phones have come out.
"It's lovely to hear that when people come out of the cinema all they want to do is call their parents or kids," says Curtis over the phone from Berlin during a publicity tour for the film. "I'm very touched that it might drive people towards a happy life."
It's not all that surprising. About Time is only Curtis' third film as a director after the massively popular Love Actually and the decidedly dour The Boat That Rocked (or flopped, as the critics remarked).
However, even taking into account the other seven films he has written - among them the perennial chick-flick favourites Four Weddings and a Funeral and Notting Hill - it is without doubt his most profound and moving.
It centres on Tim (Domhnall Gleeson) who learns from his father (Curtis regular Bill Nighy) at the age of 21 that the men in the family have the ability to travel back in time.
Tim sees it as an opportunity to find love - eventually winning over the beautiful but insecure Mary (Rachel McAdams).
But where his previous films would have finished there, Curtis explores what happens next.
"I hadn't written much about family which is quite an odd thing because I come from a very close family and have four children myself," says 56-year-old New Zealand-born Curtis, who has three sons and a daughter with his partner, script editor and broadcaster Emma Freud.
"I've mainly just written about friendship and love. I came to realise that romantic comedies in fact turn into family comedies. When someone gets married, the next thing may well be that they have kids and then that family takes care of the parents.
"So I think it's just the other half of the story that I didn't deal with in my other films."
Few will be familiar with Curtis' leading man - the son of Irish actor Brendan Gleeson - aside from his role as Bill Weasley in the final two Harry Potter films. But he was just who Curtis was looking for to play the sensitive yet charming Tim.
"When we first cast Hugh Grant he was pretty unknown," he says. "It was always my hope with this one to find a young guy people didn't really know because I think there's a great joy in that for the audience. It was a long search but I think the reason Domhnall is so wonderful is he has a really, really good sense of humour. I adore that.
"When I told Bill about the film he said 'I'll do it but I won't do any acting'," Curtis says. "He wanted to do something that would remind people of their own dad. It's such a discreet performance by him and I think that's why people are so touched by him with this role."
Curtis himself grew up in a close-knit family, living in countries including Sweden and the Philippines before moving to England when he was 11.
Like Tim, he too enjoyed time by the sea with his family and games of table tennis with his father from an early age until his mid-30s.
"I never quite spotted the fact he was always a little bit worse than me and I now have that suspicion that he maybe let me win sometimes," Curtis recalls fondly.
Brought up in such a loving environment, it's little wonder his films are so sentimental - something that tends to grate on many cynics but for which Curtis makes no apologies.
"There is a sort of conspiracy to say things that are happy or romantic are in some ways unrealistic but I don't buy into that at all," he says.
"I was by the beach in Suffolk the other day and when I stopped to look there were thousands of people walking along, old couples having cups of tea, fathers and mothers playing with their children. As far as I could see there were no serial killers there at all.
"Yet for some reason my films are called 'sentimental and unrealistic' while films about serial killers are called 'searingly realistic portrayals of modern life'. I don't see that at all. I am quite glad to do a film about a happy family."
But Curtis, who in the past five years has lost both his parents, always injects a bittersweet element into his films - and About Time is no exception.
While time travel is initially fun for Tim - most notably when he gets the chance to perfect the first time he has sex with Mary - he soon learns his gift can't save him from the sorrows and ups and downs that affect all families.
"What I was interested in really was that thing about messing up and being able to fix it," Curtis explains.
"You know the sort of comical romantic thing of how you are bound to bluff up your first date but then also the idea when things go wrong for members of your family it will be lovely to go back in time to try to fix things."
Indeed, it was while filming About Time that Curtis was reminded about the importance of making the most of now. He came to the decision to fold up his director's chair and spend more time with his family - though he intends to keep writing."Bill said to me while we were walking down the beach making this film 'Maybe next time we are walking down a beach we should be walking down a beach without 50 people rushing up and fixing our hair and telling us we are running out of time'. I guess we are both listening to the message of the movie."