diff --git a/cores/esp32/esp32-hal-misc.c b/cores/esp32/esp32-hal-misc.c
index 27f5ad23..09383fbd 100644
--- a/cores/esp32/esp32-hal-misc.c
+++ b/cores/esp32/esp32-hal-misc.c
@@ -115,7 +115,7 @@ unsigned long IRAM_ATTR micros()
 
 unsigned long IRAM_ATTR millis()
 {
-    return (unsigned long) (esp_timer_get_time() / 1000);
+    return (unsigned long) (esp_timer_get_time() / 1000ULL);
 }
 
 void delay(uint32_t ms)