Matt Smith was completely caught off guard after discovering that High Valyrian, the fictional language spoken throughout House of the Dragon, is available to learn on Duolingo.

The revelation came during a recent cast interview as the actors reflected on their experiences learning and performing the language for the HBO fantasy series. For a show where speaking High Valyrian is practically part of the job description, the discovery sparked an unexpectedly amusing exchange.

What made the moment even funnier was that Smith appeared genuinely unaware that fans could already study the language outside the world of Westeros.

The moment unfolded during a recent interview with ET, when the cast was asked about learning High Valyrian and whether they had ever considered using Duolingo to help master the language. When the interviewer pointed out that High Valyrian is actually available on the language-learning platform, Smith looked genuinely stunned by the revelation.

"Is it?... Really?" Speaking to ET, the actor responded: His disbelief immediately drew laughter from the rest of the group as fellow cast member Phoebe Campbell confirmed that the fictional language is indeed available on Duolingo.

The surprise only seemed to grow as Smith learned more about the course, including the fact that it is taught through the app's famous owl mascot. For someone who has spent years portraying Daemon Targaryen and speaking High Valyrian on screen, the discovery appeared to be completely new information.

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The exchange quickly became one of the most entertaining moments from the interview, with fans enjoying the irony that one of Westeros' most recognizable Valyrian speakers had no idea the language had become accessible to anyone with a smartphone.

While the Duolingo revelation may have surprised Smith, learning High Valyrian itself has long been a significant part of life for the cast. During the same conversation with ET, Emma D'Arcy revealed that both they and Smith had gone through multiple High Valyrian oral examinations while working on the series. According to D'Arcy, mastering the language requires far more preparation than viewers may realize.

The actor also joked that Smith's academic background should have given him an advantage, prompting a playful exchange between the co-stars. D'Arcy noted that Smith had attended Oxford, while Smith quickly pointed out that the university did not exactly offer courses in High Valyrian. The actor then jokingly suggested that perhaps it was time to return and change that.

The conversation offered a glimpse into one of the more unusual challenges facing the cast of House of the Dragon. Beyond learning battle choreography, navigating dragons, and delivering emotionally charged performances, the actors must also become comfortable speaking a fully constructed language created specifically for George R. R. Martin's fantasy world. And while fans can apparently turn to Duolingo for a helping hand, Smith's reaction suggests that even some of the stars of the franchise are still catching up with how far the fandom has taken High Valyrian.

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If Duolingo offered lessons in more fictional languages, which one would you want to learn next: High Valyrian, Dothraki, Elvish, or Klingon? Let us know in the comments.