diff --git a/esphome/components/esp8266/hal.cpp b/esphome/components/esp8266/hal.cpp
index ef93a95273..56910e5b39 100644
--- a/esphome/components/esp8266/hal.cpp
+++ b/esphome/components/esp8266/hal.cpp
@@ -1,6 +1,7 @@
 #ifdef USE_ESP8266
 
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 
 #include <Arduino.h>
 #include <core_esp8266_features.h>
diff --git a/esphome/core/hal/hal_esp8266.h b/esphome/core/hal/hal_esp8266.h
index 976b697686..b6e3b1ee3c 100644
--- a/esphome/core/hal/hal_esp8266.h
+++ b/esphome/core/hal/hal_esp8266.h
@@ -66,8 +66,6 @@ __attribute__((always_inline)) inline void arch_init() {}
 __attribute__((always_inline)) inline uint32_t arch_get_cpu_cycle_count() { return esp_get_cycle_count(); }
 __attribute__((always_inline)) inline uint32_t arch_get_cpu_freq_hz() { return F_CPU; }
 
-uint32_t arch_get_cpu_cycle_count();
-
 }  // namespace esphome
 
 #endif  // USE_ESP8266