2 files changed, 4 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/date_time/zones.rb b/activesupport/lib/active_support/core_ext/date_time/zones.rb
index 98565e6750..6002d4ad2a 100644
--- a/activesupport/lib/active_support/core_ext/date_time/zones.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/zones.rb
@@ -12,6 +12,8 @@ class DateTime
   #
   #   DateTime.new(2000).in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
   def in_time_zone(zone = ::Time.zone)
+    return self unless zone
+
     ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.__send__(:get_zone, zone))
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/time/zones.rb b/activesupport/lib/active_support/core_ext/time/zones.rb
index adc9fe3824..a02402aa3f 100644
--- a/activesupport/lib/active_support/core_ext/time/zones.rb
+++ b/activesupport/lib/active_support/core_ext/time/zones.rb
@@ -73,6 +73,8 @@ class Time
   #
   #   Time.utc(2000).in_time_zone('Alaska')  # => Fri, 31 Dec 1999 15:00:00 AKST -09:00
   def in_time_zone(zone = ::Time.zone)
+    return self unless zone
+
     ActiveSupport::TimeWithZone.new(utc? ? self : getutc, ::Time.__send__(:get_zone, zone))
   end
 end