diff --git a/nrf5/modules/ubluepy/modubluepy.h b/nrf5/modules/ubluepy/modubluepy.h
index 24f01f49bb..6ac0421ccf 100644
--- a/nrf5/modules/ubluepy/modubluepy.h
+++ b/nrf5/modules/ubluepy/modubluepy.h
@@ -134,5 +134,6 @@ typedef struct _ubluepy_advertise_data_t {
 } ubluepy_advertise_data_t;
 
 typedef void (*ubluepy_gap_evt_callback_t)(mp_obj_t self, uint16_t event_id, uint16_t conn_handle, uint16_t length, uint8_t * data);
+typedef void (*ubluepy_gatts_evt_callback_t)(mp_obj_t self, uint16_t event_id, uint16_t attr_handle, uint16_t length, uint8_t * data);
 
 #endif // UBLUEPY_H__