diff --git a/source/_integrations/light.mqtt.markdown b/source/_integrations/light.mqtt.markdown
index 067f6799edb..774b013eb4d 100644
--- a/source/_integrations/light.mqtt.markdown
+++ b/source/_integrations/light.mqtt.markdown
@@ -711,7 +711,7 @@ state_topic:
   required: false
   type: string
 supported_color_modes:
-  description: A list of color modes supported by the list. This is required if `color_mode` is `True`. Possible color modes are `onoff`, `brightness`, `color_temp`, `hs`, `xy`, `rgb`, `rgbw`, `rgbww`, `white`.
+  description: A list of color modes supported by the list. This is required if `color_mode` is `True`. Possible color modes are `onoff`, `brightness`, `color_temp`, `hs`, `xy`, `rgb`, `rgbw`, `rgbww`, `white`. Note that if `onoff` **or** `brightness` are used, that must be the _only_ value in the list.
   required: false
   type: list
 unique_id: