diff --git a/requests/_internal_utils.py b/requests/_internal_utils.py
new file mode 100644
index 00000000..0456017c
--- /dev/null
+++ b/requests/_internal_utils.py
@@ -0,0 +1,17 @@
+from .compat import is_py2, builtin_str
+
+
+def to_native_string(string, encoding='ascii'):
+    """Given a string object, regardless of type, returns a representation of
+    that string in the native string type, encoding and decoding where
+    necessary. This assumes ASCII unless told otherwise.
+    """
+    if isinstance(string, builtin_str):
+        out = string
+    else:
+        if is_py2:
+            out = string.encode(encoding)
+        else:
+            out = string.decode(encoding)
+
+    return out
diff --git a/requests/cookies.py b/requests/cookies.py
index 4a6bedd0..856fd45e 100644
--- a/requests/cookies.py
+++ b/requests/cookies.py
@@ -14,7 +14,7 @@ import time
 import calendar
 import collections
 
-from . import utils
+from ._internal_utils import to_native_string
 from .compat import cookielib, urlparse, urlunparse, Morsel
 
 try:
@@ -57,7 +57,7 @@ class MockRequest(object):
         if not self._r.headers.get('Host'):
             return self._r.url
         # If they did set it, retrieve it and reconstruct the expected domain
-        host = utils.to_native_string(self._r.headers['Host'], encoding='utf-8')
+        host = to_native_string(self._r.headers['Host'], encoding='utf-8')
         parsed = urlparse(self._r.url)
         # Reconstruct the URL as we expect it
         return urlunparse([
diff --git a/requests/utils.py b/requests/utils.py
index 4b2126e6..f7d4e37f 100644
--- a/requests/utils.py
+++ b/requests/utils.py
@@ -20,10 +20,11 @@ import warnings
 
 from . import __version__
 from . import certs
+# noinspection PyUnresolvedReferences
+from ._internal_utils import to_native_string
 from .compat import parse_http_list as _parse_list_header
-from .compat import (quote, urlparse, bytes, str, OrderedDict, unquote, is_py2,
-                     builtin_str, getproxies, proxy_bypass, urlunparse,
-                     basestring)
+from .compat import (quote, urlparse, bytes, str, OrderedDict, unquote,
+                     getproxies, proxy_bypass, urlunparse, basestring)
 from .cookies import RequestsCookieJar, cookiejar_from_dict
 from .structures import CaseInsensitiveDict
 from .exceptions import InvalidURL, InvalidHeader, FileModeWarning
@@ -770,22 +771,6 @@ def get_auth_from_url(url):
     return auth
 
 
-def to_native_string(string, encoding='ascii'):
-    """Given a string object, regardless of type, returns a representation of
-    that string in the native string type, encoding and decoding where
-    necessary. This assumes ASCII unless told otherwise.
-    """
-    if isinstance(string, builtin_str):
-        out = string
-    else:
-        if is_py2:
-            out = string.encode(encoding)
-        else:
-            out = string.decode(encoding)
-
-    return out
-
-
 # Moved outside of function to avoid recompile every call
 _CLEAN_HEADER_REGEX_BYTE = re.compile(b'^\\S[^\\r\\n]*$|^$')
 _CLEAN_HEADER_REGEX_STR = re.compile(r'^\S[^\r\n]*$|^$')