Outlander stars Sam Heughan and Caitríona Balfe have been heating up the set of their hit show for years but off-screen the pair share a rather unique relationship too. MORE: Outlander actor Sam Heughan wows fans with muscly post-workout photo – see reactionThe TV couple who play happily married couple Jamie and Claire Fraser have had fans yearning for them to become lovebirds in real life, but the co-stars have refused to ruin their "incredible friendship" with romance. Here we look at their most memorable interactions and comments from the co-stars who can't praise each other enough...WATCH: Inside Outlander's Sam Heughan and Caitriona Balfe’s real-life friendshipWhile Sam remains single, Caitriona secretly married music executive, Tony McGill, in 2019, however, the Irish star's marriage hasn't dulled her friendship with her onscreen husband and they've only got the sweetest things to say about one another. MORE: 5 questions we desperately need answering in Outlander season sevenDespite their amazing chemistry, when Sam and Caitriona first met things were awkward.