"One of the ways I dealt with it was that I wanted it to be significantly different in some way," says Vikings creator Michael Hirst. "One of the ways we did that was the song. It’s music that is meant to elicit and provoke deep emotions because you don’t understand the lyrics — they’re in ancient Scottish Gaelic. We hired these people and I didn’t tell anyone what was happening... Then I invited the crew and whoever was around on the day — the cast — to come in and listen to this singer. It was a live performance, which made it even more special. And by the time she’d finished singing, everybody in the studio was in tears." ALSO: Wednesday's episode was filmed after an "extremely intense rehearsal period."