diff --git a/Lib/functools.py b/Lib/functools.py
index 214523c..92276bd 100644
--- a/Lib/functools.py
+++ b/Lib/functools.py
@@ -388,7 +388,7 @@ def _make_key(args, kwds, typed,
         return key[0]
     return _HashedSeq(key)
 
-def lru_cache(maxsize=128, typed=False):
+def lru_cache(maxsize=128, typed=False, cache=None):
     """Least-recently-used cache decorator.
 
     If *maxsize* is set to None, the LRU features are disabled and the cache
@@ -420,18 +420,20 @@ def lru_cache(maxsize=128, typed=False):
         raise TypeError('Expected maxsize to be an integer or None')
 
     def decorating_function(user_function):
-        wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo)
+        wrapper = _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo, cache)
         return update_wrapper(wrapper, user_function)
 
     return decorating_function
 
-def _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo):
+def _lru_cache_wrapper(user_function, maxsize, typed, _CacheInfo, cache):
     # Constants shared by all lru cache instances:
     sentinel = object()          # unique object used to signal cache misses
     make_key = _make_key         # build a key from the function arguments
     PREV, NEXT, KEY, RESULT = 0, 1, 2, 3   # names for the link fields
 
-    cache = {}
+    if cache is None:
+        cache = {}
+
     hits = misses = 0
     full = False
     cache_get = cache.get    # bound method to lookup a key or return None
diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index cf0b95d..cfb0e4b 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -1113,6 +1113,25 @@ class TestLRU:
         for attr in self.module.WRAPPER_ASSIGNMENTS:
             self.assertEqual(getattr(g, attr), getattr(f, attr))
 
+    def test_lru_cache_with_specified_cache(self):
+        cache = {}
+
+        @self.module.lru_cache(maxsize=None, cache=cache)
+        def f(n):
+            return n
+
+        data = (42, "test", (55, 66))
+
+        for i in data:
+            f(i)
+
+        # modify cache data to make sure it use our cachedict
+        for i in cache.keys():
+            cache[i] *= 2
+
+        for i in data:
+            self.assertEqual(f(i), i*2)
+
     @unittest.skipUnless(threading, 'This test requires threading.')
     def test_lru_cache_threaded(self):
         n, m = 5, 11
diff --git a/Modules/_functoolsmodule.c b/Modules/_functoolsmodule.c
index 035d3d9..b4d042e 100644
--- a/Modules/_functoolsmodule.c
+++ b/Modules/_functoolsmodule.c
@@ -1,4 +1,3 @@
-
 #include "Python.h"
 #include "structmember.h"
 
@@ -913,17 +912,17 @@ bounded_lru_cache_wrapper(lru_cache_object *self, PyObject *args, PyObject *kwds
 static PyObject *
 lru_cache_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
-    PyObject *func, *maxsize_O, *cache_info_type, *cachedict;
+    PyObject *func, *maxsize_O, *cache_info_type, *cachedict = NULL;
     int typed;
     lru_cache_object *obj;
     Py_ssize_t maxsize;
     PyObject *(*wrapper)(lru_cache_object *, PyObject *, PyObject *);
     static char *keywords[] = {"user_function", "maxsize", "typed",
-                               "cache_info_type", NULL};
+                               "cache_info_type", "cachedict", NULL};
 
-    if (!PyArg_ParseTupleAndKeywords(args, kw, "OOpO:lru_cache", keywords,
+    if (!PyArg_ParseTupleAndKeywords(args, kw, "OOpOO:lru_cache", keywords,
                                      &func, &maxsize_O, &typed,
-                                     &cache_info_type)) {
+                                     &cache_info_type, &cachedict)) {
         return NULL;
     }
 
@@ -951,8 +950,13 @@ lru_cache_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         return NULL;
     }
 
-    if (!(cachedict = PyDict_New()))
-        return NULL;
+    if (cachedict == NULL || cachedict == Py_None) {
+        if (!(cachedict = PyDict_New()))
+            return NULL;
+    } else {
+        Py_INCREF(cachedict);
+    }
+
 
     obj = (lru_cache_object *)type->tp_alloc(type, 0);
     if (obj == NULL) {