diff --git a/django/template/defaultfilters.py b/django/template/defaultfilters.py
index ef7ae8679d1..53b9ade716b 100644
--- a/django/template/defaultfilters.py
+++ b/django/template/defaultfilters.py
@@ -448,7 +448,7 @@ def safeseq(value):
     individually, as safe, after converting them to strings. Return a list
     with the results.
     """
-    return [mark_safe(str(obj)) for obj in value]
+    return [mark_safe(obj) for obj in value]
 
 
 @register.filter(is_safe=True)
diff --git a/django/utils/numberformat.py b/django/utils/numberformat.py
index c6f9af68935..4dc37ae22bb 100644
--- a/django/utils/numberformat.py
+++ b/django/utils/numberformat.py
@@ -23,7 +23,7 @@ def format(number, decimal_sep, decimal_pos=None, grouping=0, thousand_sep='',
     use_grouping = use_grouping and grouping != 0
     # Make the common case fast
     if isinstance(number, int) and not use_grouping and not decimal_pos:
-        return mark_safe(str(number))
+        return mark_safe(number)
     # sign
     sign = ''
     if isinstance(number, Decimal):
diff --git a/django/utils/safestring.py b/django/utils/safestring.py
index 2da467a079c..5128add6227 100644
--- a/django/utils/safestring.py
+++ b/django/utils/safestring.py
@@ -5,7 +5,7 @@ that the producer of the string has already turned characters that should not
 be interpreted by the HTML engine (e.g. '<') into the appropriate entities.
 """
 
-from django.utils.functional import Promise, wraps
+from django.utils.functional import wraps
 
 
 class SafeData:
@@ -79,8 +79,6 @@ def mark_safe(s):
     """
     if hasattr(s, '__html__'):
         return s
-    if isinstance(s, (str, Promise)):
-        return SafeText(s)
     if callable(s):
         return _safety_decorator(mark_safe, s)
-    return SafeText(str(s))
+    return SafeText(s)