The 45-year-old star has reprised the role of Mark Renton for the new Danny Boyle-directed movie and although he was initially reluctant to appear in the follow-up, Ewan is now convinced he made the correct decision.
Speaking at the premiere of 'T2 Trainspotting' in Edinburgh, Scotland, he explained: "I don't think any of us were in any doubt once we read the script.
"Before we read it, it was something that was on my mind - you don't want to make a bad sequel to 'Trainspotting' that would damage its reputation in any way."
Danny, meanwhile, said the sequel once again shines a light on the disaffected youth in Scotland, revealing the entertaining storyline even affords him the luxury of sneaking in his "own agenda and nobody minds".
The acclaimed director told Sky News: "Scotland and its independence and its bipolar relationship with the UK and England is something I've benefited from in my career, and you have to behave in a respectful way, they don't take nonsense here."
Danny's thoughts were echoed by Irvine Welsh, who wrote the books on which the films are based.
The novelist said 'T2 Trainspotting' reflects Scotland's changing identity.
He said: "Scotland has become a much more outward-looking and Europe-orientated place - that's why there's so much anxiety about Brexit, being taken out of that.
"The film wanted to reflect that growing multi-culturalism as well."
'T2 Trainspotting' is partly based on the novel 'Porno' and also features the likes of Ewen Bremner, Jonny Lee Miller, and Robert Carlyle.
The movie is set 20 years after the original and sees Mark return to Scotland to make amends with his friends Daniel 'Spud' Murphy and Simon 'Sick Boy' Williamson.