How House Of The Dragon's Showrunner Kept The Latest Cameo A Secret

In the lore of Game of Thrones, the ruined castle, Harrenhal, has a reputation for being haunted. Prince Daemon Targaryen (Matt Smith) discovered that there may be some truth to those rumors in House of the Dragon Season 2 Episode 3. But the vision that Daemon saw there may be only the beginning for one of the show's original cast members who unexpectedly returned to the series.

Warning: the following contains spoilers from House of the Dragon Season 2 episode 3. If you haven't seen the episode or don't want to know what's in it, stop reading now.

Near the end of the episode, Daemon is drawn out of his room at Harrenhal before he encounters his estranged wife, Rhaenyra, reattaching the head of the murdered prince, Jaehaerys Targaryen. But instead of Emma D'Arcy's adult Rhaenyra, Daemon sees her younger self as portrayed by former cast member Milly Alcock, who was recently cast as the next Supergirl.

Alcock only portrayed Rhaenyra for the first five episodes of the series, before D'Arcy took over the role after a series of time jumps. According to showrunner Ryan Condal, Alcock was happy to return despite her busy schedule. He also said that she was available for a few days of filming, which suggests that we haven't seen the last of young Rhaenyra.

"It was very easy in terms of will," Condal told EW. "We were excited about the prospect. Milly was eager to come back and everybody was excited to have her back... She's very busy, so it was a tricky thing to navigate around the schedule, but we essentially had her in for a couple of days right at the start of production. I think one of our greatest feats was keeping that a secret all the way through, given the fact that it happened right at the beginning."

The scene also introduced an unknown female character who predicted that Daemon will die at Harrenhal. That too is part of the prince's storyline in Season 2.

"As you'll see [Daemon's] story at Harrenhal unfold, there is an element of Daemon having to reckon with his past and choices that he's made and things that he's done," added Condal.

House of the Dragon Season 2 will continue on July 7 on HBO and Max.