Gabaldon, who is a consultant on the hit TV adaptation of her multi-million selling novels, already had a huge fan base before Outlander hit TV screens in 2014.
Speaking at a literary event at Hopetoun House, on the outskirts of the Capital, the US author told fans during a Q&A session how Heughan sought her advice dealing with social media before he became a star.
The Scot, originally from New Galloway, had only around a dozen followers at the time. Since starring as Highland warrior Jamie Fraser in Outlander, the 38-year-old now has over 500,000, as well as dedicated fan groups around the world.
Gabaldon, who has nearly 280,000 Twitter followers herself, and 700,000 on Facebook, said: “When we started all of this, Sam Heughan was on Twitter and had like 12 followers at that point but naturally that kind of exploded.
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“At one point he wrote to me and he said, ‘how do you handle this, your fans are crazy’ - he meant that in a good way - and I said ‘I’ll tell you’.