diff --git a/CHANGELOG.md b/CHANGELOG.md
index ca7ae10c09f..68ba931d02f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## UNRELEASED
 
+### Fixed
+  - Fixed ValueError when `ff.create_annotated_heatmap` passes `rgba()` colors into `to_rgb_color_list` [#3478](https://github.com/plotly/plotly.py/issues/3478)
+
 ### Added
 
   - `text_auto` argument to `px.bar`, `px.histogram`, `px.density_heatmap`, `px.imshow` [#3518](https://github.com/plotly/plotly.py/issues/3518)
@@ -15,7 +18,6 @@ This project adheres to [Semantic Versioning](http://semver.org/).
     - texttemplate for histogram-like traces
     - text for heatmap-like traces
 
-
 ## [5.4.0] - 2021-11-15
 
 ### Fixed
diff --git a/packages/python/plotly/plotly/figure_factory/_annotated_heatmap.py b/packages/python/plotly/plotly/figure_factory/_annotated_heatmap.py
index c251234efc2..58773082457 100644
--- a/packages/python/plotly/plotly/figure_factory/_annotated_heatmap.py
+++ b/packages/python/plotly/plotly/figure_factory/_annotated_heatmap.py
@@ -1,7 +1,7 @@
 from __future__ import absolute_import, division
 
-from plotly import exceptions, optional_imports
 import plotly.colors as clrs
+from plotly import exceptions, optional_imports
 from plotly.figure_factory import utils
 from plotly.graph_objs import graph_objs
 from plotly.validators.heatmap import ColorscaleValidator
@@ -150,9 +150,10 @@ def create_annotated_heatmap(
 
 
 def to_rgb_color_list(color_str, default):
-    if "rgb" in color_str:
-        return [int(v) for v in color_str.strip("rgb()").split(",")]
-    elif "#" in color_str:
+    color_str = color_str.strip()
+    if color_str.startswith("rgb"):
+        return [int(v) for v in color_str.strip("rgba()").split(",")]
+    elif color_str.startswith("#"):
         return clrs.hex_to_rgb(color_str)
     else:
         return default