diff --git a/Foundation/DateFormatter.swift b/Foundation/DateFormatter.swift
index 31e5a69374..a1f1cae455 100644
--- a/Foundation/DateFormatter.swift
+++ b/Foundation/DateFormatter.swift
@@ -97,7 +97,7 @@ open class DateFormatter : Formatter {
 
     internal func _setFormatterAttributes(_ formatter: CFDateFormatter) {
         _setFormatterAttribute(formatter, attributeName: kCFDateFormatterIsLenient, value: isLenient._cfObject)
-        _setFormatterAttribute(formatter, attributeName: kCFDateFormatterTimeZone, value: timeZone?._cfObject)
+        _setFormatterAttribute(formatter, attributeName: kCFDateFormatterTimeZone, value: _timeZone?._cfObject)
         if let ident = _calendar?.identifier {
             _setFormatterAttribute(formatter, attributeName: kCFDateFormatterCalendarName, value: Calendar._toNSCalendarIdentifier(ident).rawValue._cfObject)
         } else {
@@ -166,11 +166,31 @@ open class DateFormatter : Formatter {
         }
     }
 
-    /*@NSCopying*/ open var locale: Locale! = .current { willSet { _reset() } }
+    /*@NSCopying*/ internal var _locale: Locale? { willSet { _reset() } }
+    open var locale: Locale! {
+        get {
+            guard let locale = _locale else { return .current }
+            return locale
+        }
+        set {
+            _locale = newValue
+        }
+    }
 
     open var generatesCalendarDates = false { willSet { _reset() } }
 
-    /*@NSCopying*/ open var timeZone: TimeZone! = NSTimeZone.system { willSet { _reset() } }
+    /*@NSCopying*/ internal var _timeZone: TimeZone? { willSet { _reset() } }
+    open var timeZone: TimeZone! {
+        get {
+            guard let timeZone = _timeZone else {
+                return (CFDateFormatterCopyProperty(_cfObject, kCFDateFormatterTimeZone) as! NSTimeZone)._swiftObject
+            }
+            return timeZone
+        }
+        set {
+            _timeZone = timeZone
+        }
+    }
 
     /*@NSCopying*/ internal var _calendar: Calendar! { willSet { _reset() } }
     open var calendar: Calendar! {
diff --git a/TestFoundation/TestDateFormatter.swift b/TestFoundation/TestDateFormatter.swift
index d0d69e9d9f..fe2346e232 100644
--- a/TestFoundation/TestDateFormatter.swift
+++ b/TestFoundation/TestDateFormatter.swift
@@ -22,6 +22,8 @@ class TestDateFormatter: XCTestCase {
             ("test_customDateFormat", test_customDateFormat),
             ("test_setLocalizedDateFormatFromTemplate", test_setLocalizedDateFormatFromTemplate),
             ("test_dateFormatString", test_dateFormatString),
+            ("test_setLocaleToNil", test_setLocaleToNil),
+            ("test_setTimeZoneToNil", test_setTimeZoneToNil),
             ("test_dateFrom", test_dateFrom),
         ]
     }
@@ -332,6 +334,30 @@ class TestDateFormatter: XCTestCase {
         }
     }
 
+    func test_setLocaleToNil() {
+        let f = DateFormatter()
+        // Locale should be the current one by default
+        XCTAssertEqual(f.locale, .current)
+
+        f.locale = nil
+
+        // Locale should go back to current.
+        XCTAssertEqual(f.locale, .current)
+
+        // A nil locale should not crash a subsequent operation
+        let result: String? = f.string(from: Date())
+        XCTAssertNotNil(result)
+    }
+
+    func test_setTimeZoneToNil() {
+        let f = DateFormatter()
+        // Time zone should be the system one by default.
+        XCTAssertEqual(f.timeZone, NSTimeZone.system)
+        f.timeZone = nil
+        // Time zone should go back to the system one.
+        XCTAssertEqual(f.timeZone, NSTimeZone.system)
+    }
+
     func test_dateFrom() throws {
         let formatter = DateFormatter()
         formatter.timeZone = TimeZone(identifier: "UTC")