The Fast Show comedians predicted that their new History channel series, in which they tour the counties of Great Britain, will be a success due to their authentic bond.
Speaking to Digital Spy, Thomson noted: "We breathe life into a tired old format, which is a superb way of putting things, because what you have is an on-screen camaraderie that shows.
"We're genuine friends, we're not two comics. We've not gone, 'Harry Hill, Les Dennis, put them in a car and send them around England'."
He added: "We've always been mates, but [with] constraints of marriage and children and everything we hadn't seen each other. And then they put us back together and it's worked. And it shows."
On how the series came about, Day jested: "They basically... said, 'Can you get anyone from The Fast Show?' [History] said, 'Could you get Mark [Williams]?' I said, 'No'. [They] said, 'Can you get Charlie [Higson]?' 'No.'
"We're friends anyway and it really was that simple. What was nice was me and him were never the best line learners - see there's no lines. You just meet people and talk."
Thomson also said that No County For Old Men should educate viewers as well as entertain them.
"We tried to take elements from all the things that get thumbs up in popular culture at the moment," he said. "We tried to pour a bit of everything that would be interesting enough.
"Without going too intellectual on things we wanted to be informative, but at the same time we wanted to appear that we were learning it for the first time as well."
The pair have expressed hope that they can continue working together on another series of The Fast Show.
No County For Old Men begins tomorrow (April 17) at 10pm on History.
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