Danny Boyle reckons he and Ewan McGregor would have resolved their differences much sooner had they just resorted to a good, old-fashioned punch-up.
"I betrayed Ewan and we didn't talk to each other for quite a long time," says the director of T2: Trainspotting, on which he and the Scottish actor were finally reunited, 20 years on.
"What we should have done is what (McGregor's character Renton) and Sick Boy do (in the sequel) when they finally meet. They bash each other with pool cues.
"Instead, we sat moping and being very British and not saying anything emotional."
Betrayal is a theme that runs all the way through T2, which features all the actors from the original 1996 film, including Jonny Lee Miller, Ewen Bremner and Robert Carlyle.
In the sequel, a near-death experience is the catalyst for Renton returning home to Edinburgh, ostensibly to make amends to the mates he ripped off (to the tune of 16,000 pounds).
"That meta-level is definitely at work," said Boyle on Thursday ahead of the film's Sydney premiere.
"Some people won't even spot it and that's fine. But for us, it was very personal. And I think we were all aware of that as we were making it."
McGregor and Boyle fell out after the director cast Leonardo di Caprio as the lead in his 2000 thriller The Beach. McGregor felt the role had been promised to him.
"It is a kind of love affair with an actor that you have worked with three times (in a row) like that," says Boyle, who also collaborated with McGregor on Shallow Grave and A Life Less Ordinary.
"He really is a beautiful actor. And I missed him terribly. I replaced him with all sorts of other people, weirdly, who are similar to him - like Cillian Murphy."
Far from being fraught, Boyle says the pair's working relationship felt very natural on the set of T2.
Not only is he keen to work with McGregor again, Boyle says he already had a project in mind. But at this early stage in negotiations, he is not prepared to discuss any details.
T2: Trainspotting opens in New Zealand on February 23.