diff --git a/kasa/transports/tpaptransport.py b/kasa/transports/tpaptransport.py
index 3a6471417..aa59a5aa3 100644
--- a/kasa/transports/tpaptransport.py
+++ b/kasa/transports/tpaptransport.py
@@ -394,7 +394,8 @@ def _sec1_to_xy(sec1: bytes, curve: ec.EllipticCurve) -> tuple[int, int]:
 
     @staticmethod
     def _xy_to_uncompressed(x: int, y: int, curve: ec.EllipticCurve) -> bytes:
-        numbers = ec.EllipticCurvePublicNumbers(x, y, curve)
+        # ecdsa may return gmpy2.mpz; cryptography requires builtin int.
+        numbers = ec.EllipticCurvePublicNumbers(int(x), int(y), curve)
         public_key = numbers.public_key()
         return public_key.public_bytes(
             encoding=serialization.Encoding.X962,