Warning: This article contains mild spoilers about the season seven premiere of Game of Thrones. It also spoils minor plot points of the Harry Potter films.

Harry Potter fans may have gotten a strange sense of déjà vu during last night’s Game of Thrones season opener. That’s because the HBO series’ creators appear to have dropped in a subtle reference to the Harry Potter film franchise—and the Internet, in a moment of truly esoteric nerd trivia, picked up on it immediately.

The Easter egg came when Samwell Tarly, eager to discover an obscure bit of history that could help Westeros fend off the advancing White Walkers, asks the archmaester Ebrose for access to the restricted section of the Citadel’s library.

Devoted fantasy fans will recall that in another world, at another time, a young Voldemort asked Professor Slughorn for permission to enter the restricted section of the library at Hogwarts. The connection? Jim Broadbent, the real-life muggle actor who played Slughorn in the final three movies of the Harry Potter franchise, made his Game of Thrones debut last night playing Ebrose.

It seems that no matter where Broadbent goes, no matter how far he travels across fantasy universes, he can’t escape eager pupils trying to meddle in parts of the library where they don’t belong.

[h/t: Independent]