ɪn tˈuː θˈaʊzənd sˈɛvəntˌiːn, fˈɜːθ dʒˈɔɪnd ðə kˈæst ʌvðɪ ˌeɪtʃbˌiːˈoʊ sˈɪɹiz ɡˈeɪm ʌv θɹˈoʊnz ɪn ˈiːstwɑːtʃ, ɐn ˈɛpɪsˌoʊd ʌv sˈiːzən sˈɛvən æz ˌɑːɹtʃmˈaɪstɚ sˈændhuː.
In 2017, Firth joined the cast of the HBO series Game of Thrones in Eastwatch, an episode of Season 7 as Archmaester Sandhu.