diff --git a/Lib/email/utils.py b/Lib/email/utils.py
@@ -57,10 +54,15 @@
 specialsre = re.compile(r'[][\\()<>@,:;".]')
 escapesre = re.compile(r'[\\"]')
 
-# How to figure out if we are processing strings that come from a byte
-# source with undecodable characters.
-_has_surrogates = re.compile(
-    '([^\ud800-\udbff]|\A)[\udc00-\udfff]([^\udc00-\udfff]|\Z)').search
+# How to figure out if we are processing strings that come from a byte source
+# with undecodable characters.  This is a self replacing function because the
+# re compile is a significant source of import overhead, but the pre-compiled
+# search function is the fastest run time check.  See issue 11454.
+def _has_surrogates(s):
+    import email.utils
+    f = re.compile('[\udc80-\udcff]').search
+    email.utils._has_surrogates = f
+    return f(s)
 
 # How to deal with a string containing bytes before handing it to the
 # application through the 'normal' interface.