Danny Boyle's 1996 dark dramedy 'Trainspotting,' based on the Irvine Welsh novel of the same name, follows a group of friends in a low-income area of 1980s Edinburgh, Scotland, as they try to kick their heroin habit. The film launched the careers of its young stars, including Ewan McGregor and Kelly Macdonald, and is ranked at number 10 on the British Film Institute's list of 100 greatest films of all time. Eighteen years later, we revisit the cast of this edgy classic and see what they're up to now. 

Ewan McGregor, Mark "Rent Boy" Renton

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Then: Ewan McGregor played Mark Renton, the film's main protagonist who goes by the nickname "Rent Boy" and who, along with his friends, desperately tries to kick his heroin habit. McGregor previously appeared in Danny Boyle's directorial debut, 'Shallow Grave,' but it was 'Trainspotting' that made him a household name.

Now: McGregor went on to star in films like 'Emma' and 'Velvet Goldmine' before landing the major role of young Obi-Wan Kenobi in George Lucas' 'Star Wars' prequel trilogy. He's also appeared in 'Moulin Rouge,' 'Big Fish' and 'The Island,' working with big-name directors like Baz Luhrmann, Tim Burton and Michael Bay. In 2013, he appeared in 'Jack the Giant Slayer' and 'August: Osage County,' and he can be seen next in the long-troubled 'Jane Got a Gun' with Natalie Portman.

Boyle stated that he's hoping to get a sequel to 'Trainspotting' ready in time for the film's 20th anniversary in 2016, one that would reunite (at least some of) the original cast members. For one, McGregor said it would be an "extraordinary" experience to reprise his role.

Ewen Bremner, Daniel "Spud" Murphy

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Then: Ewen Bremner played Daniel "Spud" Murphy, Mark's simple-minded but well-intentioned friend. Bremner actually played the role of Mark Renton in an earlier stage adaptation of Welsh's book.

Now: Bremner went on to make quite the career for himself, appearing in the films 'Snatch,' 'Pearl Harbor,' 'Black Hawk Down,' 'The Rundown' and 'Alien vs. Predator.' Bremner guest starred on an episode of 'My Name Is Earl' and recently reunited with McGregor for 'Jack the Giant Slayer.' He can be seen next in the sci-fi film 'Snowpiercer,' which still has yet to set a US release, though you can pre-order the French version on DVD and Blu-ray.

Jonny Lee Miller, Simon "Sick Boy" Williamson

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Then: Jonny Lee Miller played Simon Williamson (aka "Sick Boy"), a con artist with few morals. Miller previously appeared in the film 'Hackers' with Angelina Jolie and Matthew Lillard.

Now: It took Miller a little longer to cement his star status: he appeared in both the BBC television and film versions of 'Mansfield Park,' and in the films 'Dracula 2000,' 'Melinda and Melinda' and 'Aeon Flux.' In 2008, he starred on the short-lived series 'Eli Stone' and had a recurring role on 'Dexter.' He recently starred in the vampire films 'Byzantium' and 'Dark Shadows,' and is currently best known for playing Sherlock Holmes on the CBS TV series 'Elementary.'

Robert Carlyle, Francis "Franco" Begbie

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Then: Robert Carlyle played Francis Begbie, a sociopath who often picks fights with people for seemingly no reason at all. Carlyle said he portrayed the character as a closeted gay man whose violent outbursts were a defense mechanism meant to keep people from discovering the truth, while author Irvine Welsh confirmed that he wrote Begbie with that intention.

Now: Carlyle went on to appear in 'The Full Monty' and the James Bond film 'The World is Not Enough' before reuniting with director Danny Boyle for 'The Beach' in 2000. He also appeared in '28 Weeks Later,' the sequel to the Boyle-directed '28 Days Later.' Carlyle starred on the sci-fi series 'Stargate Universe' and currently portrays Rumplestiltskin/Mr. Gold on the ABC fairy tale series 'Once Upon a Time.'

Kevin McKidd, Tommy MacKenzie

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Then: Kevin McKidd made his big-screen debut as Tommy, a clean-cut athlete who eventually caves and takes up the heroin habit with his friends when his girlfriend dumps him.

Now: It would still take several years before McKidd became a major star -- until then, he appeared in British films like 'Hideous Kinky' with Kate Winslet and 'Topsy-Turvy.' In 2005 he landed the role of Lucius Vorenus on the HBO series 'Rome,' and went on to appear in the films 'Kingdom of Heaven,' 'Hannibal Rising' and the first 'Percy Jackson' film. Since 2008, McKidd has played Dr. Owen Hunt on 'Grey's Anatomy,' and he recently reunited with 'Trainspotting' co-star Kelly Macdonald for the 2012 animated film 'Brave.'

Kelly Macdonald, Diane Coulston

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Then: Kelly Macdonald also made her acting debut in 'Trainspotting.' The 19-year-old actress played 15-year-old Diane, whom Mark meets in a disco and returns home with, only to later discover that she lives with her parents and isn't as old as Mark thought.

Now: It also took Macdonald a few years to become a recognizable star, appearing in films like 'Elizabeth,' 'Gosford Park,' 'Finding Neverland' and 'Nanny McPhee.' In 2007, she appeared in the Coen Brothers' 'No Country for Old Men,' and since 2010 she's played the role of Margaret Schroeder on the HBO series 'Boardwalk Empire,' which is set to enter its fifth and final season in 2014. As previously mentioned, Macdonald lent her voice to the animated film 'Brave,' and recently appeared in Joe Wright's adaptation of 'Anna Karenina.'

Peter Mullan, Swanney "Mother Superior"

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Then: Peter Mullan, who previously appeared in Danny Boyle's directorial debut, 'Shallow Grave,' starred as "Mother Superior," the group's drug dealer. You might have also seen him alongside Mel Gibson in 'Braveheart.'

Now: Mullan is also known for roles in 'Session 9,' 'Children of Men' and the 'Red Riding' trilogy. He's starred on British series like 'The Trial of Tony Blair' and 'The Fixer,' and was recently nominated for an Emmy for his supporting role alongside Elisabeth Moss on the Sundance original series 'Top of the Lake.' His recent film credits include 'War Horse' and 'Sunshine on Leith.'

Shirley Henderson, Gail

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Then: One of Shirley Henderson's first big roles was in 'Trainspotting' as Gail, the lady friend with whom Spud goes home and shares a very memorable and horrifying encounter.

Now: Henderson reunited with Kevin McKidd for 'Topsy-Turvy,' and is also known for roles in the 'Bridget Jones' Diary' films and for playing the role of Moaning Myrtle in the 'Harry Potter' series. She appeared in the films '24 Hour Party People,' 'Marie Antoinette,' and recently reunited with Kelly Macdonald for 'Anna Karenina.' Henderson also recently starred in 'Filth,' another adaptation of an Irvine Welsh story starring James McAvoy.