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.
“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’.