"Outlander" stars Sam Heughan and Caitriona Balfe, who share screen space in the season 1 of the series, are said to be more than just friends. The grapevine abuz with the news that they are dating.

The couple shares a blazing onscreen chemistry and this seems to be seeping into their real life, according to reports. Heughan even gushed about Balfe in an interview when she was selected for the role of Claire.

"We just knew straightaway that she was the right one. We just started chatting in the test before we started the audition. And we just seemed to get on. Her humour is fantastic. She's great fun to work with. She's very hardworking, a wonderful actress, very natural. It's been really fun to see where the relationship goes between us," he said about Balfe to Entertianment Weekly.

The couple has always maintained that they are just friends but several media reports suggested that there could be something more as they are so close to each other even during public appearances. They never fail to praise each other in interviews and have often called each other "sexy", according to a report by KDrama Stars.

They also share some steamy love scenes in the series, adding mroe fuel to the rumours. They reportedly spent more then a week in one room for a steamy wedding night scene, they spent more then a week in one room, as per the reports.

"We spent a week, basically, in a room, myself and Cat, with very little clothes on. It was pretty interesting," Heughan said as reported by E!Oneline.

Even executive producer Anne Kenney said that the two care for each other.

"The relationship off-screen with them, they're just very affectionate with each other," gushed Kenney, adding, "They're very caring with each other, so that's lovely and kind of infuses the relationship between Jamie and Claire."

However, Balfe has claimed on many occasions that she is single.