The Fermanagh rally driver, who won the World Production Rally Championship in 2004, jumped behind the wheel for a succession of dramatic car scenes for the new blockbuster movie currently on release in cinemas across the country.
"I'm a lot younger than Ray Winstone but unfortunately for me they thought I looked a bit like him, so they used me as a stunt double for him when driving the cars," Niall revealed. "He did keep telling me how good looking I was, but I think that's just because I was supposed to be playing him!"
In the movie, a remake of the classic 1970s TV cop series, Ray Winstone's character drives a new Ford Focus ST while the bad guys race through the English countryside in a 500 horse power Jaguar FXR. The film makers paid little heed to the value of the cars however, and although Niall has bent more than his fair share of bodywork during his rallying career, even he felt uncomfortable with the treatment he had to deal out to the brand new supercars.
"I think there were 27 miles on the Jaguar and 15 miles on the Focus when we had to start slamming them off each other going down a road," he said. "It was kind of all wrong, but it was very good fun! I haven't seen the film yet but there is a bit where Ben Drew is hanging out the window and shooting back at the other car, and that was fun, but we did go through a lot of cars. We had five Focuses and we destroyed three of them, and we had three Jaguars and destroyed two of them."
While the actors are all big names in their own field, Niall found them very down to earth and approachable.
"Allen Leech who is in Downton Abbey and Ben Drew and Ray Winstone were really, really nice people and very easy to get on with," he said. "One of the nights we had a party and we had really good craic with them."
While the movie was Niall's first appearance on the big screen, he is no stranger to the cameras having worked with the Top Gear television programme for almost two years.
"I could be doing anything for Top Gear," he said. "It could be just driving one of the tracking vehicles or driving some of the cars. I enjoy the track stuff, but when you go away with them it's really good. It's a well-oiled machine with a very small group of people who actually run it. There are only about 50 people on the whole programme. We are going to Morocco now in a few days. The producers from Top Gear are starting a series of programmes and this is the first one of them."
But on the question of the identity of 'The Stig', Niall is not forthcoming.
"I can't say. The Presenters are very good, but the Stig is very quiet. He doesn't say much."
Niall's main focus remains competitive rallying. Along with co-driver Marshall Clarke they have been competing in the Chinese Rally Championship this season in a Skoda Octavia, but in the future he has not ruled out following in the footsteps of former British Rally Champion Mark Higgins, who now makes a living from performing on the world's biggest movie sets.
"He's just finished the Bond movie and he's on '2 fast 2 Furious' at the minute," revealed Niall. "Personally I am still out in China but if that driving gets less then I'll maybe get into that work more and more. It sounds very glamorous but it's not, but it does pay well and it's nice to be involved in something unusual like that."