"Even seven or eight years later, people come up and say that scene was their favourite part," says Gillebride MacMillan.

The South-Uist-born Gaelic singer played Gwyllyn the Bard in the first season of Diana Gabaldon's time-travelling blockbuster, which returns for a 7th season tonight with the American revolution in full swing.

He performs the hauntingly beautiful song The Woman of Balnain in Castle Leoch, a scene that is pivotal for main character Clare Randall, played by Caitríona Balfe.

Gillebride was picked after answering an advert on social media from the show's producers who were looking for a Gaelic singer to play clan chief Collum MacKenzie's bard.

His brief appearance in the show kick-started "life-changing" opportunities for the native speaker.

He is now Outlander's Gaelic advisor, he wrote a song for the new series and has travelled the world performing for Outlander's devoted fans.

"It's hard to believe it's almost ten years since I was cast as Gwyllyn the Bard," he says.

"It was an incredible honour to be part of the show.

"It was quite a small part but it was quite an important part for a lot of the fans.

"It was pivotal to Clare's story because it gave her hope that she could go back through the stones.

"So I was telling the story of the Woman of Balnain who had gone through the stones and managed to go back.

"A lot of the fans grabbed onto season one, because it was in the Highlands and it was so, so special to them."

The song was composed by the show's American composer Bear McCreary, and the Glasgow-based musician was asked to choose two traditional songs for series one.

"I chose a Jacobite song and a love song from the Gaelic tradition," he says.

"Two of those songs featured on the soundtrack and it just snowballed from there."

READ MORE: Glasgow to host Outlander conference attended by author Diana Gabaldon 

"As a result of that part I've been all over the world. It just shows what one song can do," he says.

The Herald:

Gillebride is a senior Gaelic lecturer at the University of Glasgow, which awarded author Diana Gabaldon an honourary degree last year and is to host a major conference dedicated to Outlander from July 18-22. 

He also made an appearance in Men in Kilts, Sam Heugan and Graham McTavish's TV road trip around Scotland.

He got to know Gabaldon and says he was delighted when she asked if she could use his name [the Anglicised version is Gilbert} for a character in her latest book.

He says the new series has "quite a bit of Gaelic in it " but isn't giving anything away about locations that might give away plotlines, for those who haven't read the books.

The Herald:

He agrees that Outlander has probably done more to raise the profile of Gaelic than anything else in TV or radio.

"A funny thing I heard is that on the website LearnGaelic.net they used to get a huge amount of hits at 3am on a Monday morning and of course that was all these people in Canada and the U.S watching Outlander on a Sunday evening. 

READ MORE: Outlander is back: The best of the box sets

"Much of the success of DuoLingo is associated with Outlander," he says. "I know people, friends, who have started learning Gaelic because of Outlander and who have come to proficiency as a result of Outlander.

"It's really incredible. 

"It was mentioned on the news today, this idea of using Gaelic as a selling point for Scotland. 

"From my own experience, I go abroad and teach Gaelic and Gaelic song to people who may have Scottish ancestry.

The Herald:

"They may not but just fell in love with Scotland through the books and the show."

He said people in other parts of the world have a greater understanding of the advantages of bilingualism. "We don't quite have that in Scotland, yet.

"If you think about Caitriona Balfe, she speaks Irish because you learn Irish in school but most of the other Scottish actors didn't have another language."

He said it was important that the show did not shy away from the history of the language in the Highlands and "how much was done in many ways to eradicate it from the landscape".

The Herald:

The University of Glasgow is working to create networks for young people who have gone through Gaelic Medium Education to ensure they have opportunities to use the language when they leave school.

The university runs a three-week course where students go to South Uist and are immersed in the language and culture.

READ MORE: Tourism attraction featured in Outlander goes up for sale 

"One thing that is really important for younger people is actually having a reason for speaking Gaelic.

The Herald:

"When you see a US TV show using the language, giving it pride of place it's so important for the types of feelings people have about the language.

"I've had so many opportunities from using my Gaelic.

"There are opportunities for teaching, journalism, BBC and also increasingly art and music.

"The Outlander effect means it's slightly easier for Gaelic artists and musicians to find a market but you have to do it in a way that keeps the traditions so you are not selling something that is fake.

"What I found with Outlander fans is that they love the show but they also love finding out what Scotland is like today, what the music is like.

"They don't want their idea of Scotland, they want the real Scotland.

"It's so important to use the heritage and culture and sell it in a way that is authentic."