Told he, at 61, seemed much too young to play the role, Nighy replied: "Yes, I know! Thank God, somebody worked that out!"
"When I went for the job I at least thought I was going for Father Christmas and they said, 'No, no, no, Jim Broadbent is playing Father Christmas.' And so it was Grandsanta, who was 136. Thank you for noticing that I'm not quite 136 yet," he told UPI in New York recently. "They were looking for someone who's 4-foot-tall with no hair and no teeth and they thought of me, which is weird. It turns out I have an inner codger. He's getting ready now, so in the future, he'll be up to speed. I think you don't have to be 136 to be curmudgeonly or codgery, but it helps. It was good fun."
"Arthur Christmas," a 3-D computer-animated movie from Aardman Animations and Sony Pictures Animation, is about how Santa Claus now employs cutting-edge technology and legions of hardworking elves to deliver presents to every child in the world on Christmas Eve.
Nighy plays Santa's cranky father, who is called out of retirement by his grandson Arthur to deliver one mislaid gift the old-fashioned way -- with a sleigh, reindeer and a map.
Broadbent plays the glory-loving current Santa, while Hugh Laurie plays Steve, his ambitious, high tech-minded son who can't wait until dad retires, so he can take over the family business. James McAvoy plays the title character, Steve's tender-hearted brother and the only one who seems to truly understand and enjoy the magic of Christmas.
The project reunited Nighy and McAvoy, who played father-and-son journalists in the British miniseries "State of Play" eight years ago.
"I've been his father, now I'm his grandfather," Nighy grimaced. "No, it was great. He and I worked together a few times [on this.] Because, usually with animation, you're on your own and somebody else is in some other part of the world doing their bit. But the Christmas dinner scene, we all did together except for Hugh, who was shooting ['House'] in Los Angeles, I presume. But James, Jim and Imelda [Staunton as Mrs. Claus] and I, the Christmas family, were all together. James and I did quite a lot together, obviously, because we were in that sleigh together for two years or something and it was very nice to see James. It's always nice to do business with him."
Asked if he was aware his 2003 romantic comedy "Love Actually" has become a contemporary Christmas classic, Nighy admitted: "I do like the fact that 'Love Actually' has sort of entered the Christmas language in England and America. It's become part of the whole thing. If you didn't see 'Love Actually' -- even if you don't like 'Love Actually' -- you'd feel like something was missing. I did seriously think when I read the script for 'Arthur Christmas,' if they do this half-way decently, it will be a perennial. I do want to be part of that."
So, what was it like watching "Arthur Christmas" once it was all put together?
"It was fantastic," he said. "I think I saw it [for the first time] under the best of circumstances, which was in a cinema full of kids, which was marvelous. ... I thought it was absolutely brilliant. This is not public relations. I just sat there and was completely, as we say in England, gobsmacked. I thought they'd done a brilliant job and I was very moved by it. It moves at such a speed. It's so cool the way it shifts and you want to see it again. And very, very good jokes. Very cool jokes."
The actor said he suspected the movie would be good because the script director Sarah Smith wrote with Peter Baynham was so terrific.
"I desperately wanted to be in it," Nighy recalled. "I had to audition to be in it because they have to know that you have a voice that will suit, so they have to try you out. It's not like a regular job where they recklessly just give you the job and hope you can play it or it's kind of close to you. They need to try you out. ... There are lots of jobs you want, but then there is a shorter list of jobs you really, really want and I really wanted to be in this."
Nighy's credits include the "Underworld" film franchise, as well as "Page 8," "Harry Potter and the Deathly Hallows, Part 1," "Valkyrie," "Flushed Away," "Pirates of the Caribbean: Dead Man's Chest," "Pirates of the Caribbean: At World's End" and "Blow Dry."
"Arthur Christmas" is in theaters now.
Notable deaths of 2014 [PHOTOS]