diff --git a/LayoutTests/imported/w3c/ChangeLog b/LayoutTests/imported/w3c/ChangeLog
index 4ca6e7d7d3b30..b2d8f450b8a9c 100644
--- a/LayoutTests/imported/w3c/ChangeLog
+++ b/LayoutTests/imported/w3c/ChangeLog
@@ -1,3 +1,15 @@
+2019-04-02  Chris Dumez  <cdumez@apple.com>
+
+        [Fetch API] Allow used body replacement in Request constructor
+        https://bugs.webkit.org/show_bug.cgi?id=183703
+        <rdar://problem/49425609>
+
+        Reviewed by Youenn Fablet.
+
+        Rebaseline WPT test now that one more check is passing.
+
+        * web-platform-tests/fetch/api/request/request-disturbed-expected.txt:
+
 2019-04-02  Chris Dumez  <cdumez@apple.com>
 
         Unreviewed, rolling out r243551.
diff --git a/LayoutTests/imported/w3c/web-platform-tests/fetch/api/request/request-disturbed-expected.txt b/LayoutTests/imported/w3c/web-platform-tests/fetch/api/request/request-disturbed-expected.txt
index 5b57d0a279417..e32dcb5ed8d3f 100644
--- a/LayoutTests/imported/w3c/web-platform-tests/fetch/api/request/request-disturbed-expected.txt
+++ b/LayoutTests/imported/w3c/web-platform-tests/fetch/api/request/request-disturbed-expected.txt
@@ -3,7 +3,7 @@ PASS Request's body: initial state
 PASS Request without body cannot be disturbed 
 PASS Check cloning a disturbed request 
 PASS Check creating a new request from a disturbed request 
-FAIL Check creating a new request with a new body from a disturbed request Request input is disturbed or locked.
+PASS Check creating a new request with a new body from a disturbed request 
 FAIL Input request used for creating new request became disturbed assert_equals: body should not change expected object "[object ReadableStream]" but got object "[object ReadableStream]"
 FAIL Input request used for creating new request became disturbed even if body is not used assert_true: bodyUsed is true when request is disturbed expected true got false
 PASS Check consuming a disturbed request 
diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index f66952bbb00ad..f171a68c4914b 100644
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,19 @@
+2019-04-02  Chris Dumez  <cdumez@apple.com>
+
+        [Fetch API] Allow used body replacement in Request constructor
+        https://bugs.webkit.org/show_bug.cgi?id=183703
+        <rdar://problem/49425609>
+
+        Reviewed by Youenn Fablet.
+
+        Allow used body replacement in Request constructor as per:
+        - https://github.com/whatwg/fetch/pull/675
+
+        No new tests, rebaseline existing test.
+
+        * Modules/fetch/FetchRequest.cpp:
+        (WebCore::FetchRequest::initializeWith):
+
 2019-04-02  Chris Dumez  <cdumez@apple.com>
 
         Unreviewed, rolling out r243551.
diff --git a/Source/WebCore/Modules/fetch/FetchRequest.cpp b/Source/WebCore/Modules/fetch/FetchRequest.cpp
index 9f2eb36eed79e..c37def31fdd3b 100644
--- a/Source/WebCore/Modules/fetch/FetchRequest.cpp
+++ b/Source/WebCore/Modules/fetch/FetchRequest.cpp
@@ -203,9 +203,6 @@ ExceptionOr<void> FetchRequest::initializeWith(const String& url, Init&& init)
 
 ExceptionOr<void> FetchRequest::initializeWith(FetchRequest& input, Init&& init)
 {
-    if (input.isDisturbedOrLocked())
-        return Exception {TypeError, "Request input is disturbed or locked."_s };
-
     m_request = input.m_request;
     m_options = input.m_options;
     m_referrer = input.m_referrer;
@@ -240,6 +237,9 @@ ExceptionOr<void> FetchRequest::initializeWith(FetchRequest& input, Init&& init)
         if (setBodyResult.hasException())
             return setBodyResult.releaseException();
     } else {
+        if (input.isDisturbedOrLocked())
+            return Exception { TypeError, "Request input is disturbed or locked."_s };
+
         auto setBodyResult = setBody(input);
         if (setBodyResult.hasException())
             return setBodyResult.releaseException();