The pair has been close friends ever since Burns cast Britton as his sister-in-law in his directorial debut The Brothers McMullen in 1995, and she insists it was a pivotal turning point in her life.
She explains, "I feel like I owe Eddie my career... (After The Brothers McMullen), it was a stunning change. Suddenly, I had an agent and exciting opportunities."
As a result, Britton was determined to jet between the West Coast set of her hit TV series American Horror Story and the Big Apple shoot for the holiday drama to make sure she could finish the job, because quitting was not an option.
She adds, "Doors had been closing in my face for years... So if he calls (to offer her work), I say yes."
However, playing lovers in The Fitzgerald Family Christmas was more than a little uncomfortable for both Britton and Burns because they are as close as siblings.
Burns says, "Honestly, it felt a little incestuous. But we laughed, then tried to muster up the intimacy. There's a reason why we're friends."