It has millions of devoted fans around the world, and has been credited with delivering a major boost to the Scottish film and tourism industries.
Outlander, the story of time-travelling surgeon Claire and her Jacobite Highlander husband Jamie, is due to return to our screens next week when its fourth season airs on Amazon Prime in the UK and Starz in America.
In a wide-ranging interview with BBC Scotland, Rutherglen actor Richard Rankin - who plays historian Roger Mackenzie in the series - spoke about what the hit US show's impact has been on Scotland, how the country needs to capitalise on the "Outlander effect", and what we can expect from his character.
So far in Outlander, Jamie (Sam Heughan) and Claire's (Caitriona Balfe) love story has woven through key moments of the 18th Century including the Jacobite rising in Scotland, the political intrigue of Paris and the Jamaican slave trade.
Season 4 of the drama, which is an adaptation of books by Diana Gabaldon, sees the pair shipwrecked in North Carolina in the years preceding the American Revolution.
Meanwhile, Richard's whisky-loving character has fallen in love with Jamie and Claire's daughter Brianna (Sophie Skelton) in the Scottish Highlands and Boston in the 1960s.
"I think where the popularity of Outlander comes from is just the sheer volume of content in the story," said Richard. "That is what has always got me is just how much there is in there, both in terms of historical fact and historical fiction."
The biggest impact of the show in Scotland so far has been on its tourism and film industries.
Doune, Blackness and Craigmiller castles and the University of Glasgow are among the many Scottish locations used to date in Outlander.
Earlier this year, it emerged that Scotland has outperformed the rest of the UK in attracting visitors to its tourist attractions for the sixth year running. This has been dubbed the "Outlander effect".
Meanwhile, major Hollywood films such as Fast and the Furious, World War Z and Avengers: Infinity War have all filmed in Scotland in recent times.
For Richard, Outlander has helped to bring success to both sectors.
He said: "There is an influx of people to Scotland, who are coming solely to Scotland because they want to visit places that we had shot in, or inspired parts of the story in Outlander. Various places we have been to, which is most of Scotland.
"It is amazing to have seen the impact Outlander has had on Scotland. The TV and film industry was struggling at a point. I don't think there was enough commitment to it. I don't think there was enough investment in it, so when Outlander came in it was very refreshing.
"It was quite revitalising for the Scottish film and television industry. We now have a four-sound stage studio in Cumbernauld. It is a huge step forward."
The Cumbernauld studio is Outlander's own facility. A spokeswoman from Sony Pictures, one of the companies behind the programme's production, told the BBC all of the upcoming season of Outlander was filmed in Scotland while up to 300 Scottish crew members regularly work on the American show.
While nothing is confirmed yet, it is safe to assume that filming for Outlander season five will also take place in Scotland next year.
However, the lack of a major film studio in Scotland is something that frustrates Richard and he believes the Scottish creative industry is not capitalising on the platform that shows like Outlander have given it.
Earlier this month, plans for the Scottish studio were dealt another setback when a court ruled that a tenant farmer cannot be removed from land outside Edinburgh which had been earmarked for the site.
Richard added: "It will make a huge difference if we invest and have our own studio to film in. That is what is missing, and ultimately what loses Scotland a lot of film work is because we don't have a studio.
"I hear these stories all the time of big productions coming to Scotland, and scouting locations, and finding exteriors and perfect locations to be filming in and then they say 'oh, where is your studio, where will we shoot our interior stuff', and we are like 'aah, we don't actually have a studio'.
"A lot of work has ended up over in Ireland, and over in Belfast, because they have a studio and a similar landscape."
Outlander's fans can look forward to seeing Richard in the fourth, fifth and sixth season of the programme, while the former Burnistoun and The Replacement star is currently filming in the second season of the BBC One drama Trust Me.
"I think fans can expect to see a very different side to Roger in this season" added Richard.
"He goes on quite the journey. His relationship with Brianna is tested to the absolute limits. For those who aren't familiar with the books, it is probably a journey they aren't expecting to see."