diff --git a/Lib/email/charset.py b/Lib/email/charset.py
index 9e5ee67bfe6..a44b711aa4b 100644
--- a/Lib/email/charset.py
+++ b/Lib/email/charset.py
@@ -377,6 +377,8 @@ class Charset:
         """
         # 7bit/8bit encodings return the string unchanged (module conversions)
         if self.body_encoding is BASE64:
+            if isinstance(string, str):
+                string = string.encode(self.output_charset)
             return email.base64mime.body_encode(string)
         elif self.body_encoding is QP:
             return email.quoprimime.body_encode(string)
diff --git a/Lib/email/test/test_email.py b/Lib/email/test/test_email.py
index 6793df50c6c..44a47c54fcf 100644
--- a/Lib/email/test/test_email.py
+++ b/Lib/email/test/test_email.py
@@ -535,7 +535,7 @@ class TestEncoders(unittest.TestCase):
         # whose output character set is 7bit gets a transfer-encoding
         # of 7bit.
         eq = self.assertEqual
-        msg = MIMEText('\xca\xb8', _charset='euc-jp')
+        msg = MIMEText('文', _charset='euc-jp')
         eq(msg['content-transfer-encoding'], '7bit')
 
 
@@ -1080,6 +1080,33 @@ class TestMIMEText(unittest.TestCase):
         eq(msg.get_charset().input_charset, 'us-ascii')
         eq(msg['content-type'], 'text/plain; charset="us-ascii"')
 
+    def test_7bit_input(self):
+        eq = self.assertEqual
+        msg = MIMEText('hello there', _charset='us-ascii')
+        eq(msg.get_charset().input_charset, 'us-ascii')
+        eq(msg['content-type'], 'text/plain; charset="us-ascii"')
+
+    def test_7bit_input_no_charset(self):
+        eq = self.assertEqual
+        msg = MIMEText('hello there')
+        eq(msg.get_charset(), 'us-ascii')
+        eq(msg['content-type'], 'text/plain; charset="us-ascii"')
+        self.assertTrue('hello there' in msg.as_string())
+
+    def test_utf8_input(self):
+        teststr = '\u043a\u0438\u0440\u0438\u043b\u0438\u0446\u0430'
+        eq = self.assertEqual
+        msg = MIMEText(teststr, _charset='utf-8')
+        eq(msg.get_charset().output_charset, 'utf-8')
+        eq(msg['content-type'], 'text/plain; charset="utf-8"')
+        eq(msg.get_payload(decode=True), teststr.encode('utf-8'))
+
+    @unittest.skip("can't fix because of backward compat in email5, "
+        "will fix in email6")
+    def test_utf8_input_no_charset(self):
+        teststr = '\u043a\u0438\u0440\u0438\u043b\u0438\u0446\u0430'
+        self.assertRaises(UnicodeEncodeError, MIMEText, teststr)
+
 
 
 # Test complicated multipart/* messages
diff --git a/Misc/NEWS b/Misc/NEWS
index 68f36fcc930..4c60de3f223 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -398,6 +398,10 @@ C-API
 Library
 -------
 
+- Charset.body_encode now correctly handles base64 encoding by encoding
+  with the output_charset before calling base64mime.encode.  Passes the
+  tests from 2.x issue 1368247.
+
 - Issue #8845: sqlite3 Connection objects now have a read-only in_transaction
   attribute that is True iff there are uncommitted changes.