diff --git a/esphome/components/mqtt/mqtt_backend_esp32.h b/esphome/components/mqtt/mqtt_backend_esp32.h
index bd2d2a67b25..adba0cf0046 100644
--- a/esphome/components/mqtt/mqtt_backend_esp32.h
+++ b/esphome/components/mqtt/mqtt_backend_esp32.h
@@ -139,7 +139,8 @@ class MQTTBackendESP32 final : public MQTTBackend {
     this->lwt_retain_ = retain;
   }
   void set_server(network::IPAddress ip, uint16_t port) final {
-    this->host_ = ip.str();
+    char ip_buf[network::IP_ADDRESS_BUFFER_SIZE];
+    this->host_ = ip.str_to(ip_buf);
     this->port_ = port;
   }
   void set_server(const char *host, uint16_t port) final {