JOHN GORDON SINCLAIR

The character: Gregory, a gangly lovelorn teenager with an all-consuming crush on the school's new female football ace, Dorothy. He lives with his parents, but takes romantic advice from his worldly-wise little sister Madeline (Allison Forster).

The player: An apprentice electrician and 18-year-old Glasgow Youth Theatre regular, John Gordon Sinclair was recruited by Bill Forsyth after starring in the director's 1979 comedy debut, That Sinking Feeling.

Why we loved him: Gregory's awkward stick-insect mien, his permanently gurning coyness and befuddled vulnerability seemed to capture completely the awkward ache of adolescence. Plus he had a gift for exasperated put-downs, such as his fiery confrontation of Madeline's tiny pre-pubescent suitor, Richard (Denis Criman), which is the movie's comedy highlight. “There's nothing wrong with me, son!” he replies to Denis's innocuous ‘How are you?' “You're the one that should be worried! Seducing children? You're a freak! You're heading for big trouble. You'll run out of vices before you're 12!”

What happened next? Sinclair popped up in movies such as Erik the Viking and Britannia Hospital and in the TV shows Mad about Alice and Murder in Mind. He had success on stage in the musicals The Producers and She Loves Me (for which he won an Olivier Award). His two-year engagement to the theatrical singing star Ruthie Henshall was broken off, due to work pressures, in 2002. While ultimately a return to the movie role of Gregory was ill-advised, and the belated screen sequel Gregory's Two Girls was a flop.

Where is he now? On the West End, playing a womaniser in Alan Ayckbourn's marital comedy Absurd Person Singular, and finishing his debut novel, a crime yarn set in Northern Ireland.

DEE HEPBURN

The character :Dorothy, a voluptuous teen idol with a Farah-flick and a pair of tiny white micro-shorts. She's a modern girl who believes in penalty practice, Italian romance and gender equality on the pitch.

The player: Hepburn was 19 when she made Gregory's Girl. Previously she had played a willowy Maggie in the 1978 Scottish TV production of The Prime of Miss Jean Brodie. Forsyth sent her on a six-week training course with Partick Thistle FC to improve her screen football skills.

Why we loved her: As the benign motivating object of desire, Dorothy was, on paper at least, a thankless role. And yet Hepburn's wide peering eyes and confident, quirky grin somehow managed to inject a certain unspoken sass into the part. The changing-room scene, in which she compares scars with Gregory (a nod to Spielberg's Jaws?), is given a flirtatious frisson when she discusses holidaying in Rome, sunbathing and the allure of Italian men.

What happened next? After three years as a regular on the TV soap Crossroads, as Anne-Marie Wade, and 12 years as a jobbing actress, Hepburn, then a single mum, decided to quit for good. “You get to a point in your life when you think, ‘Do I want to do this forever?'” she told the BBC's Movie Connections programme. “And although I really loved the work, I wanted to stop and have my children without limelight surrounding them.”

Where is she now? Living in East Kilbride, and working as a sales rep for a pharmaceuticals company.

ROBERT 'RAB' BUCHANAN

The character: Andy, mop-headed best friend to Gregory, equal parts voracious sexual desire and monumental sexual inexperience. He famously faints in the opening sequence when spying on a topless nurse.

The player: Like Sinclair, he had been hand-picked by Forsyth to star in That Sinking Feeling, in which he played a heist mastermind.

Why we loved him: Andy is an outright audience pleaser and, appearing in brief comedic vignettes, is responsible for much of the mirth in the movie. Accompanied by his virtually silent sidekick Charlie (Graham Thompson), he is a soft-spoken and eminently polite emissary for male inadequacy. His attempted chat-up of Clare Grogan's Susan is masterful. “Good afternoon,” he says, approaching her at the lunch table, while she chews distractedly on an apple. “Do you know that when you sneeze it comes out your nose at 100mph? It's a well known fact. 100mph! (He does a mock sneeze.) Just like that!” She stands up and, wordlessly, leaves the table.

What happened next? Buchanan had a small part in Forsyth's failed Local Hero follow-up Comfort and Joy and then he quit screen acting.

Where is he now? He works as a theatre technician at the Tollbooth Arts Centre in Stirling.

CLARE GROGAN

The character: Susan, confounding both the movie's poster image and common-held misconceptions, is the Gregory's girl of the title. A diminutive, slyly smirking minx with a black beret and a Louise Brooks bob, it is Susan who orchestrates the date that will eventually bring Gregory into her arms.

The player: Grogan was 18 when she was discovered by Forsyth in 1980, in the Spaghetti Factory restaurant in Glasgow, where she worked as a waitress. She was already a part-time singer with post-punk ambitions. Gregory's Girl was her first acting job.

Why we loved her: Although Dorothy was the traditional bombshell, Susan had a dark and edgy confidence (think Ally Sheedy in The Breakfast Club) that emerged every time she was on screen. Besides the deliciously silent sidelining of Andy, her famous mid-smooch exchange with Gregory is typical of the character's deadpan wit. “That's good,” she says, drawing breath from a long and vigorous lip-lock, “You've finally stopped kissing me like your aunty.”

What happened next? Grogan went from being a young tyro actress to a post-teen pop sensation as lead singer with the band Altered Images. Three albums and one infuriatingly catchy hit single (Happy Birthday) later and the band split up, leaving Grogan with an aborted solo career on her hands (Remember her single Love Bomb? No?). She re-formed the band in 2005 for the nostalgic Here & Now tour, performing with fellow 1980s singers Kim Wilde and Limahl. She married the Images guitarist Stephen Lironi in 1995, and kept her acting career afloat with regular roles in the likes of Taggart, EastEnders and most recently the BBC's market-trader comedy Legit.

Where is she now? She DJs on digital radio station BBC 6 Music, and is developing a television script.

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