diff --git a/ktor-client/ktor-client-darwin/darwin/src/io/ktor/client/engine/darwin/internal/DarwinUrlUtils.kt b/ktor-client/ktor-client-darwin/darwin/src/io/ktor/client/engine/darwin/internal/DarwinUrlUtils.kt
index 628de8d0229..8c85004d5f1 100644
--- a/ktor-client/ktor-client-darwin/darwin/src/io/ktor/client/engine/darwin/internal/DarwinUrlUtils.kt
+++ b/ktor-client/ktor-client-darwin/darwin/src/io/ktor/client/engine/darwin/internal/DarwinUrlUtils.kt
@@ -37,7 +37,7 @@ internal fun Url.toNSUrl(): NSURL {
         else -> host.sanitize(NSCharacterSet.URLHostAllowedCharacterSet)
     }
     if (port != DEFAULT_PORT && port != protocol.defaultPort) {
-        components.port = NSNumber(port)
+        components.port = NSNumber(int = port)
     }
 
     components.percentEncodedPath = when {