diff --git a/lib/matplotlib/colorbar.py b/lib/matplotlib/colorbar.py
index 5c37eef5190b..6c92f3795384 100644
--- a/lib/matplotlib/colorbar.py
+++ b/lib/matplotlib/colorbar.py
@@ -404,7 +404,7 @@ def __init__(self, ax, mappable=None, *, cmap=None,
             try:
                 self._formatter = ticker.FormatStrFormatter(format)
                 _ = self._formatter(0)
-            except TypeError:
+            except (TypeError, ValueError):
                 self._formatter = ticker.StrMethodFormatter(format)
         else:
             self._formatter = format  # Assume it is a Formatter or None
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
index 73c4dab9a87f..0cf098e787ee 100644
--- a/lib/matplotlib/tests/test_colorbar.py
+++ b/lib/matplotlib/tests/test_colorbar.py
@@ -15,7 +15,7 @@
     BoundaryNorm, LogNorm, PowerNorm, Normalize, NoNorm
 )
 from matplotlib.colorbar import Colorbar
-from matplotlib.ticker import FixedLocator, LogFormatter
+from matplotlib.ticker import FixedLocator, LogFormatter, StrMethodFormatter
 from matplotlib.testing.decorators import check_figures_equal
 
 
@@ -1230,3 +1230,9 @@ def test_colorbar_wrong_figure():
     fig_tl.colorbar(im)
     fig_tl.draw_without_rendering()
     fig_cl.draw_without_rendering()
+
+
+def test_colorbar_format_string_and_old():
+    plt.imshow([[0, 1]])
+    cb = plt.colorbar(format="{x}%")
+    assert isinstance(cb._formatter, StrMethodFormatter)