diff --git a/Doc/library/zipimport.rst b/Doc/library/zipimport.rst
index 912378e..3fd0595 100644
--- a/Doc/library/zipimport.rst
+++ b/Doc/library/zipimport.rst
@@ -88,6 +88,15 @@
       file wasn't found.
 
 
+   .. method:: get_filename(fullname)
+
+      Return the value ``__file__`` would be set to if the specified module
+      was imported. Raise :exc:`ZipImportError` if the module couldn't be
+      found.
+
+   .. versionadded:: 3.1
+
+
    .. method:: get_source(fullname)
 
       Return the source code for the specified module. Raise
diff --git a/Lib/test/test_zipimport.py b/Lib/test/test_zipimport.py
index 5637467..f41deaf 100644
--- a/Lib/test/test_zipimport.py
+++ b/Lib/test/test_zipimport.py
@@ -212,7 +212,7 @@
             self.assertEquals(zi.archive, TEMP_ZIP)
             self.assertEquals(zi.is_package(TESTPACK), True)
             mod = zi.load_module(TESTPACK)
-            self.assertEquals(zi._get_filename(TESTPACK), mod.__file__)
+            self.assertEquals(zi.get_filename(TESTPACK), mod.__file__)
 
             self.assertEquals(zi.is_package(packdir + '__init__'), False)
             self.assertEquals(zi.is_package(packdir + TESTPACK2), True)
@@ -224,11 +224,11 @@
             mod = sys.modules[mod_name]
             self.assertEquals(zi.get_source(TESTPACK), None)
             self.assertEquals(zi.get_source(mod_path), None)
-            self.assertEquals(zi._get_filename(mod_path), mod.__file__)
+            self.assertEquals(zi.get_filename(mod_path), mod.__file__)
             # To pass in the module name instead of the path, we must use the right importer
             loader = mod.__loader__
             self.assertEquals(loader.get_source(mod_name), None)
-            self.assertEquals(loader._get_filename(mod_name), mod.__file__)
+            self.assertEquals(loader.get_filename(mod_name), mod.__file__)
 
             # test prefix and archivepath members
             zi2 = zipimport.zipimporter(TEMP_ZIP + os.sep + TESTPACK)
@@ -257,7 +257,7 @@
             self.assertEquals(zi.prefix, packdir)
             self.assertEquals(zi.is_package(TESTPACK2), True)
             mod = zi.load_module(TESTPACK2)
-            self.assertEquals(zi._get_filename(TESTPACK2), mod.__file__)
+            self.assertEquals(zi.get_filename(TESTPACK2), mod.__file__)
 
             self.assertEquals(zi.is_package(TESTPACK2 + os.sep + '__init__'), False)
             self.assertEquals(zi.is_package(TESTPACK2 + os.sep + TESTMOD), False)
@@ -268,11 +268,11 @@
             mod = sys.modules[mod_name]
             self.assertEquals(zi.get_source(TESTPACK2), None)
             self.assertEquals(zi.get_source(mod_path), None)
-            self.assertEquals(zi._get_filename(mod_path), mod.__file__)
+            self.assertEquals(zi.get_filename(mod_path), mod.__file__)
             # To pass in the module name instead of the path, we must use the right importer
             loader = mod.__loader__
             self.assertEquals(loader.get_source(mod_name), None)
-            self.assertEquals(loader._get_filename(mod_name), mod.__file__)
+            self.assertEquals(loader.get_filename(mod_name), mod.__file__)
         finally:
             z.close()
             os.remove(TEMP_ZIP)
diff --git a/Misc/NEWS b/Misc/NEWS
index df877ad..ee1bc56 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -155,6 +155,9 @@
 Library
 -------
 
+- Issue #4512 (part 2): Promote ``ZipImporter._get_filename()`` to be a
+  public documented method ``ZipImporter.get_filename()``.
+
 - Issue #4195: The ``runpy`` module (and the ``-m`` switch) now support
   the execution of packages by looking for and executing a ``__main__``
   submodule when a package name is supplied. Initial patch by Andi
diff --git a/Modules/zipimport.c b/Modules/zipimport.c
index ba37f8b..53bc799 100644
--- a/Modules/zipimport.c
+++ b/Modules/zipimport.c
@@ -363,7 +363,7 @@
     char *fullname, *modpath;
     int ispackage;
 
-    if (!PyArg_ParseTuple(args, "s:zipimporter._get_filename",
+    if (!PyArg_ParseTuple(args, "s:zipimporter.get_filename",
                          &fullname))
         return NULL;
 
@@ -543,7 +543,7 @@
 
 
 PyDoc_STRVAR(doc_get_filename,
-"_get_filename(fullname) -> filename string.\n\
+"get_filename(fullname) -> filename string.\n\
 \n\
 Return the filename for the specified module.");
 
@@ -558,7 +558,7 @@
 	 doc_get_code},
 	{"get_source", zipimporter_get_source, METH_VARARGS,
 	 doc_get_source},
-	{"_get_filename", zipimporter_get_filename, METH_VARARGS,
+	{"get_filename", zipimporter_get_filename, METH_VARARGS,
 	 doc_get_filename},
 	{"is_package", zipimporter_is_package, METH_VARARGS,
 	 doc_is_package},