Ewan McGregor is back as the lead character, Renton, perhaps best remembered for his visit in the first film to the “Worst Toilet in Scotland.” Robert Carlyle appears as Begbie, who starts brawls with almost anyone who crosses his path; Ewen Bremner returns as the dimwitted Spud, who, in the first movie, has a memorable job interview while high on speed; and Jonny Lee Miller is back as Sick Boy, now known as Simon.
Source: wiktionary