The novel has been hailed a literary phenomenon, selling more than a million copies since it was published in 2009, and inspiring a generation to consider hunting down a long-lost love 'just in case'.
Now David Nicholls's One Day has had the Hollywood treatment, bringing some of its most memorable moments to the big screen.
For the uninitiated, the story follows dowdy Yorkshire lass Emma Morley and charismatic ladies' man Dexter Mayhew on a 20-year journey of romance and friendship that's guaranteed to leave you sobbing into your sleeve.
On screen we meet the couple in the grand surroundings of Edinburgh's Parliament Square, as they stumble home from their graduation celebrations, so it seemed the perfect point from which to begin my own One Day in the city.
The square sits just off the Royal Mile, a street that runs from Edinburgh Castle down to Holyrood Palace (the Queen's official residence in Scotland) and it's an infamous tourist magnet.
Side-stepping the many tartan and shortbread gift shops, I make the short walk to another location featured in the film, Victoria Terrace.
This split-level street is one of the most distinctive in the city and fantastic for photos. The lower level (Victoria Street) is lined with quirky little shops and cafes with brightly coloured facades, and the terrace above comprises of a pretty pedestrian walkway and balcony, from which you can watch the hustle and bustle of life below.
As daylight threatened, Emma and Dexter made for the cover of her flat in the studenty suburb of Newington, just a stone's throw away from one of the story's most romantic settings - Holyrood Park.
Like a little piece of the Scottish Highlands right in the middle of its capital city, these 650 acres of rugged parkland, are all lochs, glens and windswept hills. And at the centre of it all stands Arthur's Seat, an extinct volcano that looms above the city skyline.
Even Dexter, with his policy of not appearing impressed by anything, considers the view from the top "magnificent", and I had to agree. Clambering around the hillside and up onto the Salisbury Crags, I could see for miles, the city spread out underneath me, from the ancient castle in the distance to the post-modern Parliament building just below.
After their hike up the hill, Emma and Dexter head to his flat in the city's New Town, but before I attempted their race down the steps of Warriston Close, I decided to check out the Edinburgh of yesteryear.
Mary King's Close is a visitor attraction buried beneath the Royal Mile.
In the 1600s the city's leaders built over these 17th century streets - using them as the foundations for the current City Chambers building, now home to the City Council - but before that, they housed thousands of residents.
Conditions were grim; filth covered the streets, rats ran riot and the plague ensured an agonising death for many. Being down there in those steep, narrow, claustrophobic closes (the Scottish name for an underground street) gave me a real flavour of just how different and difficult life would have been.
Our guide assured us they were haunted by one of its most famous residents, a little girl called Annie. She's become so popular that many visitors bring toys and treats for her. Thankfully, she failed to put in an appearance during my trip.
History lesson done, I made my way out and set off on the short walk to the elegant surroundings of the Georgian New Town, just in time for a spot of lunch.
Boutique tea shop Eteaket is the kind of place I could imagine Dexter taking his glamorous mother when she came to visit. A frankly baffling number of teas are on offer, along with some delicious home-made cakes, all served up in the prettiest vintage tea sets.
Suitably refreshed, I ventured on through the New Town, circling past Dexter's Fettes Row flat back to Moray Place and Forres Street, home to some of the best-preserved examples of Georgian architecture in Europe - and the site of that kiss, captured in the movie's promotional posters.
Here, you too can pose for a snap snogging on the cobbles, but beware of the traffic. The production company closed the road to film the movie and its unlikely local bus drivers will appreciate being held up as you try to recreate that iconic shot.
The Edinburgh scenes were filmed in just five days at the beginning of August 2010, and getting those all important shots meant a lot of legwork for the crew.
As well as hiking up Arthur's Seat, they also climbed Calton Hill, in the dark, to capture one of the beautiful scene-setting sunrise shots.
Tired out from my earlier hike around Holyrood Park, I opted, instead, for the recently re-opened National Museum of Scotland.
More than 20,000 objects are contained in 36 galleries, all housed in one magnificent Victorian building. They spent £46m on the renovation and it's worth every penny.
The Grand Gallery is magnificent, like a giant glass birdcage with natural light flooding into the four-storey atrium, creating a wonderful sense of space and calm. The collection here is vast and varied, from Dolly the sheep, to the famous Lewis Chessmen, Scotland's most significant archaeological discovery.
At the end of my very busy One Day in Edinburgh, I felt I'd earned a glass of wine.
Top-end eating options abound in the city and I plumped for the famous Rutland Hotel at the west end of Princes Street. After a delicious dinner in the upstairs restaurant, I retired to the ground level Style Bar.
And as I sank into an expertly prepared cocktail, I could almost see Emma scowling, while Dexter, no doubt, would have approved.
Best for: A stunning city skyline and the inspiring architecture.
Time to go: August can be busy and expensive as the city's population doubles for the annual Edinburgh Festival.
Don't miss: A hike up Arthur's Seat for your own romantic One Day moment.
Need to know: Don't let those tramlines fool you into waiting for one. There aren't any!
Don't forget: Comfy shoes, the city is best explored on foot. And an umbrella - this is Scotland after all.
Travel facts: Claire Walker was a guest of Visit Scotland and Marketing Edinburgh. She stayed at the Holiday Inn Edinburgh - City-West, who offer two-night autumn breaks (B&B), based on two sharing from £130. For reservations call 0131 472 2024 or visit www.holidayinn.com.