diff --git a/homeassistant/components/hdmi_cec/__init__.py b/homeassistant/components/hdmi_cec/__init__.py
index 1d0b7bb34d7..3d4851d8852 100644
--- a/homeassistant/components/hdmi_cec/__init__.py
+++ b/homeassistant/components/hdmi_cec/__init__.py
@@ -333,7 +333,7 @@ def setup(hass: HomeAssistant, base_config: ConfigType) -> bool:  # noqa: C901
     def _new_device(device):
         """Handle new devices which are detected by HDMI network."""
         key = f"{DOMAIN}.{device.name}"
-        hass.data[key] = device
+        hass.data[DOMAIN][key] = device
         ent_platform = base_config[DOMAIN][CONF_TYPES].get(key, platform)
         discovery.load_platform(
             hass,
diff --git a/homeassistant/components/hdmi_cec/media_player.py b/homeassistant/components/hdmi_cec/media_player.py
index e187eb56c1b..c31daa85316 100644
--- a/homeassistant/components/hdmi_cec/media_player.py
+++ b/homeassistant/components/hdmi_cec/media_player.py
@@ -66,7 +66,7 @@ def setup_platform(
         _LOGGER.debug("Setting up HDMI devices %s", discovery_info[ATTR_NEW])
         entities = []
         for device in discovery_info[ATTR_NEW]:
-            hdmi_device = hass.data[device]
+            hdmi_device = hass.data[DOMAIN][device]
             entities.append(CecPlayerEntity(hdmi_device, hdmi_device.logical_address))
         add_entities(entities, True)
 
diff --git a/homeassistant/components/hdmi_cec/switch.py b/homeassistant/components/hdmi_cec/switch.py
index 87b19d5727f..8e6deae1394 100644
--- a/homeassistant/components/hdmi_cec/switch.py
+++ b/homeassistant/components/hdmi_cec/switch.py
@@ -27,7 +27,7 @@ def setup_platform(
         _LOGGER.info("Setting up HDMI devices %s", discovery_info[ATTR_NEW])
         entities = []
         for device in discovery_info[ATTR_NEW]:
-            hdmi_device = hass.data[device]
+            hdmi_device = hass.data[DOMAIN][device]
             entities.append(CecSwitchEntity(hdmi_device, hdmi_device.logical_address))
         add_entities(entities, True)