diff --git a/android/fixture.go b/android/fixture.go
index 883647c0a..5fc668a8b 100644
--- a/android/fixture.go
+++ b/android/fixture.go
@@ -367,15 +367,6 @@ type FixturePreparer interface {
 	// Return the flattened and deduped list of simpleFixturePreparer pointers.
 	list() []*simpleFixturePreparer
 
-	// Creates a copy of this instance and adds some additional preparers.
-	//
-	// Before the preparers are used they are combined with the current preparer, any groups of
-	// preparers are flattened, and the list is deduped so that each preparer is only used once. See
-	// the file documentation in android/fixture.go for more details.
-	//
-	// deprecated: Use GroupFixturePreparers() instead.
-	Extend(preparers ...FixturePreparer) FixturePreparer
-
 	// Create a Fixture.
 	Fixture(t *testing.T) Fixture
 
@@ -656,17 +647,12 @@ func (b *baseFixturePreparer) initBaseFixturePreparer(self FixturePreparer) {
 	b.self = self
 }
 
-func (b *baseFixturePreparer) Extend(preparers ...FixturePreparer) FixturePreparer {
-	all := dedupAndFlattenPreparers(b.self.list(), preparers)
-	return newFixturePreparer(all)
-}
-
 func (b *baseFixturePreparer) Fixture(t *testing.T) Fixture {
 	return createFixture(t, t.TempDir(), b.self.list())
 }
 
 func (b *baseFixturePreparer) ExtendWithErrorHandler(errorHandler FixtureErrorHandler) FixturePreparer {
-	return b.self.Extend(newSimpleFixturePreparer(func(fixture *fixture) {
+	return GroupFixturePreparers(b.self, newSimpleFixturePreparer(func(fixture *fixture) {
 		fixture.errorHandler = errorHandler
 	}))
 }
diff --git a/android/fixture_test.go b/android/fixture_test.go
index 8f0471560..5b810e0b7 100644
--- a/android/fixture_test.go
+++ b/android/fixture_test.go
@@ -41,7 +41,7 @@ func TestFixtureDedup(t *testing.T) {
 
 	group := GroupFixturePreparers(preparer1, preparer2, preparer1, preparer1Then2)
 
-	extension := group.Extend(preparer4, preparer2)
+	extension := GroupFixturePreparers(group, preparer4, preparer2)
 
 	GroupFixturePreparers(extension, preparer1, preparer2, preparer2Then1, preparer3).Fixture(t)
 
diff --git a/genrule/genrule_test.go b/genrule/genrule_test.go
index 2ee456d56..3f1e9f3b9 100644
--- a/genrule/genrule_test.go
+++ b/genrule/genrule_test.go
@@ -670,7 +670,8 @@ func TestGenruleAllowMissingDependencies(t *testing.T) {
 			cmd: "cat $(in) > $(out)",
 		}
        `
-	result := prepareForGenRuleTest.Extend(
+	result := android.GroupFixturePreparers(
+		prepareForGenRuleTest,
 		android.FixtureModifyConfigAndContext(
 			func(config android.Config, ctx *android.TestContext) {
 				config.TestProductVariables.Allow_missing_dependencies = proptools.BoolPtr(true)
diff --git a/java/hiddenapi_singleton_test.go b/java/hiddenapi_singleton_test.go
index dc4e8aaff..5c449e506 100644
--- a/java/hiddenapi_singleton_test.go
+++ b/java/hiddenapi_singleton_test.go
@@ -39,7 +39,8 @@ var hiddenApiFixtureFactory = android.GroupFixturePreparers(
 	prepareForJavaTest, PrepareForTestWithHiddenApiBuildComponents)
 
 func TestHiddenAPISingleton(t *testing.T) {
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 	).RunTestWithBp(t, `
 		java_library {
@@ -56,7 +57,8 @@ func TestHiddenAPISingleton(t *testing.T) {
 }
 
 func TestHiddenAPIIndexSingleton(t *testing.T) {
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		PrepareForTestWithJavaSdkLibraryFiles,
 		FixtureWithLastReleaseApis("bar"),
 		fixtureSetBootJarsProductVariable("platform:foo", "platform:bar"),
@@ -115,7 +117,8 @@ func TestHiddenAPISingletonWithSourceAndPrebuiltPreferredButNoDex(t *testing.T)
 			" replaced by the prebuilt module \"prebuilt_foo\" but unfortunately it does not provide a" +
 			" suitable boot dex jar"
 
-	hiddenApiFixtureFactory.Extend(
+	android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 	).ExtendWithErrorHandler(android.FixtureExpectsAtLeastOneErrorMatchingPattern(expectedErrorMessage)).
 		RunTestWithBp(t, `
@@ -134,7 +137,8 @@ func TestHiddenAPISingletonWithSourceAndPrebuiltPreferredButNoDex(t *testing.T)
 }
 
 func TestHiddenAPISingletonWithPrebuilt(t *testing.T) {
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 	).RunTestWithBp(t, `
 		java_import {
@@ -151,7 +155,8 @@ func TestHiddenAPISingletonWithPrebuilt(t *testing.T) {
 }
 
 func TestHiddenAPISingletonWithPrebuiltUseSource(t *testing.T) {
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 	).RunTestWithBp(t, `
 		java_library {
@@ -178,7 +183,8 @@ func TestHiddenAPISingletonWithPrebuiltUseSource(t *testing.T) {
 }
 
 func TestHiddenAPISingletonWithPrebuiltOverrideSource(t *testing.T) {
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 	).RunTestWithBp(t, `
 		java_library {
@@ -236,7 +242,8 @@ func TestHiddenAPISingletonSdks(t *testing.T) {
 	}
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
-			result := hiddenApiFixtureFactory.Extend(
+			result := android.GroupFixturePreparers(
+				hiddenApiFixtureFactory,
 				tc.preparer,
 				android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
 					variables.Always_use_prebuilt_sdks = proptools.BoolPtr(tc.unbundledBuild)
@@ -286,7 +293,8 @@ func TestHiddenAPISingletonWithPrebuiltCsvFile(t *testing.T) {
 	// Where to find the prebuilt hiddenapi files:
 	prebuiltHiddenApiDir := "path/to/prebuilt/hiddenapi"
 
-	result := hiddenApiFixtureFactory.Extend(
+	result := android.GroupFixturePreparers(
+		hiddenApiFixtureFactory,
 		fixtureSetBootJarsProductVariable("platform:foo"),
 		fixtureSetPrebuiltHiddenApiDirProductVariable(&prebuiltHiddenApiDir),
 	).RunTestWithBp(t, `
diff --git a/java/sdk_test.go b/java/sdk_test.go
index e1ec41bdc..2b1846592 100644
--- a/java/sdk_test.go
+++ b/java/sdk_test.go
@@ -402,14 +402,16 @@ func TestClasspath(t *testing.T) {
 
 			// Test again with PLATFORM_VERSION_CODENAME=REL, javac -source 8 -target 8
 			t.Run("REL + Java language level 8", func(t *testing.T) {
-				result := fixtureFactory.Extend(prepareWithPlatformVersionRel).RunTestWithBp(t, bpJava8)
+				result := android.GroupFixturePreparers(
+					fixtureFactory, prepareWithPlatformVersionRel).RunTestWithBp(t, bpJava8)
 
 				checkClasspath(t, result, true /* isJava8 */)
 			})
 
 			// Test again with PLATFORM_VERSION_CODENAME=REL, javac -source 9 -target 9
 			t.Run("REL + Java language level 9", func(t *testing.T) {
-				result := fixtureFactory.Extend(prepareWithPlatformVersionRel).RunTestWithBp(t, bp)
+				result := android.GroupFixturePreparers(
+					fixtureFactory, prepareWithPlatformVersionRel).RunTestWithBp(t, bp)
 
 				checkClasspath(t, result, false /* isJava8 */)
 			})
diff --git a/rust/project_json_test.go b/rust/project_json_test.go
index 7af463528..09d30dbde 100644
--- a/rust/project_json_test.go
+++ b/rust/project_json_test.go
@@ -28,9 +28,10 @@ import (
 // testProjectJson run the generation of rust-project.json. It returns the raw
 // content of the generated file.
 func testProjectJson(t *testing.T, bp string) []byte {
-	result := prepareForRustTest.
-		Extend(android.FixtureMergeEnv(map[string]string{"SOONG_GEN_RUST_PROJECT": "1"})).
-		RunTestWithBp(t, bp)
+	result := android.GroupFixturePreparers(
+		prepareForRustTest,
+		android.FixtureMergeEnv(map[string]string{"SOONG_GEN_RUST_PROJECT": "1"}),
+	).RunTestWithBp(t, bp)
 
 	// The JSON file is generated via WriteFileToOutputDir. Therefore, it
 	// won't appear in the Output of the TestingSingleton. Manually verify