Richard Curtis and Bill Nighy Reunite in "About Time" Murray Close/Universal Pictures Domhnall Gleeson, left, and Bill Nighy in "About Time." The occasion was a meeting with an old friend in London, where a casual chat suddenly took a turn toward the profound. "We were having a conversation about whether we were happy, and as he asked the question, I was surprised to find that I said, "Not particularly," " said Mr. Curtis, a still boyish 56. And while what was wrong wasn't immediately apparent - malaise is often a moving target - it got Mr. Curtis to thinking what would be a perfect day. "Ten years ago, we would have said, "Let's fly to Las Vegas, go out on a date with a movie star, get a phone call saying you've been nominated for an Oscar, win a million pounds," " Mr. Curtis recalled. And we both thought: We'd hate that day now. So it was that Mr. Curtis began to write the script for "About Time," a twisty, time-bending tale featuring another friend of his, Bill Nighy, alongside Domhnall Gleeson as a father and son with the magical ability to revisit - and repair - all the days of their lives. Rachel McAdams also stars as Mr. Gleeson's love interest. Mr. Nighy's character, a slightly loopy early retiree with a fondness for Dickens and table tennis, has the potential for being unbearably cute but somehow isn't. "About Time" finds Mr. Nighy - a master of arch and slightly off-center understatement who is a frequent collaborator of Mr. Curtis - once again acting as a kind of palette cleanser to Mr. Curtis's distinct brand of almost-too-sweet cinema: smart comedies that border, but never cross into, the saccharine. Mr. Nighy is the bitters to Mr. Curtis's vermouth, the slice of sharp Cheddar on a warm apple pie. And in "About Time," Mr. Nighy does so by consciously trying to do nothing at all. "I wanted to make even fewer concessions than ever before to the fact that there was a camera there," Mr. Nighy, who is 63, said during a recent joint interview with Mr. Curtis at the Mandarin Oriental hotel in Columbus Circle. That was the idea. I just wanted to do it as naturally and normally as possible and not get caught acting - in inverted commas - or making a name for myself. Mr. Nighy, of course, already made a name for himself, and largely has Mr. Curtis - and a character named Billy Mack - to thank for that. The film was "Love Actually," from 2003, the multipronged rom-com whose most touching - and funniest - story line was not romantic but platonic: the relationship between Mr. Mack, a faded rock star and ex-heroin addict, and his lumpy and long-suffering roadie (played by Gregor Fisher). It's a role that Mr. Nighy seemed born for - he is, in fact, obsessed with rock music, particularly Bob Dylan - but was never intended to play. Initially, Mr. Curtis, then starting to direct, had no intention of casting Mr. Nighy, who had built a respectable career but had not broken through to stardom. But all that changed, Mr. Curtis said, after a read-through of the script in which Mr. Nighy - as a favor to a casting director - played Billy. As Mr. Curtis remembers it, "At that read-through, the only laughs were every line that Bill said." In some ways, Mr. Nighy is an unlikely comic actor - quiet, measured, self-effacing - and even more unlikely movie star. See previous adjectives. Lanky and angular - with fingers on both hands permanently folded by a condition known as Dupuytren's contracture - Mr. Nighy treads softly when he walks, and talks, usually peering from behind blocky black glasses. His answers to questions about his acting can be painfully unpretentious. "I just studied the part," he said, for instance, when asked about "Love Actually." But that simplicity belies a deeper work ethic, friends and colleagues said. "It's literally the aim and goal of everyone in this country to work with Bill," said Ol Parker, the screenwriter of "The Best Exotic Marigold Hotel," in which Mr. Nighy played a money-strapped retiree. Mr. Parker said that Mr. Nighy "has this extraordinary ability that everything he does is incredibly idiosyncratic," something echoed by Christopher Walken, who recently worked alongside Mr. Nighy on the coming "Turks & Caicos," part of David Hare's "Page Eight" spy series seen on the BBC. Mr. Walken, no stranger to quirky characters himself, said he could see "a power to the mind" of Mr. Nighy. "Bill is one of those actors that I wish that every time I got to work it were with him," Mr. Walken said. His performance in "Love Actually" won Mr. Nighy several awards and led to a cascade of parts large and small. Over the last decade, Mr. Nighy has been quite busy, including in big-budget franchises like the "Underworld" series (playing an elder, and altogether evil, vampire) and "Pirates of the Caribbean" (playing a snarling, slimy Davy Jones).