diff --git a/lib/matplotlib/rcsetup.py b/lib/matplotlib/rcsetup.py
index 200518e80070..829646b8a784 100644
--- a/lib/matplotlib/rcsetup.py
+++ b/lib/matplotlib/rcsetup.py
@@ -367,12 +367,16 @@ def validate_color(s):
             return 'None'
     except AttributeError:
         pass
+
+    if isinstance(s, six.string_types):
+        if len(s) == 6 or len(s) == 8:
+            stmp = '#' + s
+            if is_color_like(stmp):
+                return stmp
+
     if is_color_like(s):
         return s
-    stmp = '#' + s
 
-    if is_color_like(stmp):
-        return stmp
     # If it is still valid, it must be a tuple.
     colorarg = s
     msg = ''
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
index 072959eb8ff7..4f12766b7def 100644
--- a/lib/matplotlib/tests/test_colors.py
+++ b/lib/matplotlib/tests/test_colors.py
@@ -18,7 +18,7 @@
 from numpy.testing.utils import assert_array_equal, assert_array_almost_equal
 from nose.plugins.skip import SkipTest
 
-from cycler import cycler
+from matplotlib import cycler
 import matplotlib
 import matplotlib.colors as mcolors
 import matplotlib.cm as cm
@@ -615,6 +615,14 @@ def test_cn():
     assert mcolors.to_hex("C0") == '#0343df'
     assert mcolors.to_hex("C1") == '#ff0000'
 
+    matplotlib.rcParams['axes.prop_cycle'] = cycler('color', ['8e4585', 'r'])
+
+    assert mcolors.to_hex("C0") == '#8e4585'
+    # if '8e4585' gets parsed as a float before it gets detected as a hex
+    # colour it will be interpreted as a very large number.
+    # this mustn't happen.
+    assert mcolors.to_rgb("C0")[0] != np.inf
+
 
 def test_conversions():
     # to_rgba_array("none") returns a (0, 4) array.