HBO accidentally reveals a major new "Game of Thrones" character before episode five of the series officially aired.

Towards the end of episode 4, a white walker places an infant on a pedestal made of ice. Another white walker picks up the child and touches the boy's cheek, turning his eyes ice blue. HBO's synopsis of episode four previously stated:

"A White Walker claims the baby and rides to a city of ice," the synopsis read. "The child is presented at an altar, where the Night's King greets the infant and lays a finger on its cheek. The baby's eyes turn White Walker blue."

The HBO synopsis has since been changed to read a "White Walker" instead of Night's King. Brandon Stark has previously mentioned the Night's King in his folklore stories. According to Nerdist, the mythic king was the thirteenth Lord Commander of the Night's Watch during the Age of Heroes. The Lord Commander was also named Bran Stark, though some interpretations claim he was a Bolton or an Umber.

However, in the Night's King has remained a mythical creature in the novels and making him a real character in the series is straying from the George R.R. Martin's work thus far.

Introducing the Night's King could be HBO's way of giving Martin more time to finish up the "Game of Thrones" novel series, which he is currently working on. Show co-creator David Benioff recently admitted to Vanity Fair he knows how the series will end, so the Night's King's introduction could be the writers laying out the groundwork needed to end the series.

"Last year we went out to Santa Fe for a week to sit down with him [Martin] and just talk through where things are going, because we don't know if we are going to catch up and where exactly that would be," Benioff told Vanity Fair.

"If you know the ending, then you can lay the groundwork for it," he added. "And so we want to know how everything ends. We want to be able to set things up. So we just sat down with him and literally went through every character."