diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 4e053fbd1e2..4c2f2ba6aef 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -181,10 +181,8 @@ function amp_add_amphtml_link() {
 		if ( AMP_Theme_Support::is_paired_available() ) {
 			$amp_url = add_query_arg( amp_get_slug(), '', $current_url );
 		}
-	} elseif ( is_singular() ) {
+	} elseif ( is_singular() && post_supports_amp( get_post( get_queried_object_id() ) ) ) {
 		$amp_url = amp_get_permalink( get_queried_object_id() );
-	} else {
-		$amp_url = add_query_arg( amp_get_slug(), '', $current_url );
 	}
 
 	if ( ! $amp_url ) {
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index c67be4cccf8..f1eadd8b448 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -410,20 +410,32 @@ public static function finish_init() {
 			add_filter( 'template_include', [ __CLASS__, 'serve_paired_browsing_experience' ] );
 		}
 
+		$has_query_var  = (
+			isset( $_GET[ amp_get_slug() ] ) // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			||
+			false !== get_query_var( amp_get_slug(), false )
+		);
 		$is_reader_mode = self::READER_MODE_SLUG === self::get_support_mode();
-		if ( $is_reader_mode && ! is_singular() && false !== get_query_var( amp_get_slug(), false ) ) {
+		if (
+			$is_reader_mode
+			&&
+			$has_query_var
+			&&
+			( ! is_singular() || ! post_supports_amp( get_post( get_queried_object_id() ) ) )
+		) {
 			// Reader mode only supports the singular template (for now) so redirect non-singular queries in reader mode to non-AMP version.
+			// Also ensure redirecting to non-AMP version when accessing a post which does not support AMP.
 			// A temporary redirect is used for admin users to allow them to see changes between reader mode and transitional modes.
 			wp_safe_redirect( amp_remove_endpoint( amp_get_current_url() ), current_user_can( 'manage_options' ) ? 302 : 301 );
 			return;
 		} elseif ( ! is_amp_endpoint() ) {
 			/*
-			 * Redirect to AMP-less variable if AMP is not available for this URL and yet the query var is present.
+			 * Redirect to AMP-less URL if AMP is not available for this URL and yet the query var is present.
 			 * Temporary redirect is used for admin users because implied transitional mode and template support can be
 			 * enabled by user ay any time, so they will be able to make AMP available for this URL and see the change
 			 * without wrestling with the redirect cache.
 			 */
-			if ( isset( $_GET[ amp_get_slug() ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended
+			if ( $has_query_var ) {
 				self::redirect_non_amp_url( current_user_can( 'manage_options' ) ? 302 : 301, true );
 			}
 
diff --git a/tests/php/test-amp-helper-functions.php b/tests/php/test-amp-helper-functions.php
index a01c25e9fb5..5aed421f66e 100644
--- a/tests/php/test-amp-helper-functions.php
+++ b/tests/php/test-amp-helper-functions.php
@@ -273,44 +273,87 @@ public function test_amp_add_frontend_actions() {
 	 *
 	 * @return array
 	 */
-	public function get_amphtml_urls() {
-		$post_id = self::factory()->post->create();
-		return [
-			'is_home' => [
-				home_url( '/' ),
-				add_query_arg( amp_get_slug(), '', home_url( '/' ) ),
-			],
-			'is_404'  => [
-				home_url( '/no-existe/' ),
-				add_query_arg( amp_get_slug(), '', home_url( '/no-existe/' ) ),
-			],
-			'is_post' => [
-				get_permalink( $post_id ),
-				amp_get_permalink( $post_id ),
-			],
+	public function get_reader_mode_amphtml_urls() {
+		$providers = [
+			'is_home'         => static function () {
+				return [
+					home_url( '/' ),
+					add_query_arg( amp_get_slug(), '', home_url( '/' ) ),
+					false,
+				];
+			},
+			'is_404'          => static function () {
+				return [
+					home_url( '/no-existe/' ),
+					add_query_arg( amp_get_slug(), '', home_url( '/no-existe/' ) ),
+					false,
+				];
+			},
+			'is_post'         => function() {
+				$post_id = $this->factory()->post->create();
+				return [
+					get_permalink( $post_id ),
+					amp_get_permalink( $post_id ),
+					true,
+				];
+			},
+			'is_skipped_post' => function() {
+				$skipped_post_id = self::factory()->post->create();
+				add_filter(
+					'amp_skip_post',
+					static function ( $skip, $current_post ) use ( $skipped_post_id ) {
+						if ( $current_post === $skipped_post_id ) {
+							$skip = true;
+						}
+						return $skip;
+					},
+					10,
+					2
+				);
+				return [
+					get_permalink( $skipped_post_id ),
+					amp_get_permalink( $skipped_post_id ),
+					false,
+				];
+			},
 		];
+		return array_map(
+			function( $provider ) {
+				return [ $provider ];
+			},
+			$providers
+		);
 	}
 
 	/**
 	 * Adding link when theme support is not present.
 	 *
-	 * @dataProvider get_amphtml_urls
+	 * @dataProvider get_reader_mode_amphtml_urls
 	 * @covers ::amp_add_amphtml_link()
-	 * @param string $canonical_url Canonical URL.
-	 * @param string $amphtml_url   The amphtml URL.
+	 *
+	 * @param callable $data_provider Provider.
 	 */
-	public function test_amp_add_amphtml_link_reader_mode( $canonical_url, $amphtml_url ) {
+	public function test_amp_add_amphtml_link_reader_mode( $data_provider ) {
+		list( $canonical_url, $amphtml_url, $available ) = $data_provider();
 		$this->assertFalse( current_theme_supports( AMP_Theme_Support::SLUG ) );
 		$this->assertFalse( amp_is_canonical() );
 		$get_amp_html_link = static function() {
 			return get_echo( 'amp_add_amphtml_link' );
 		};
 
-		$assert_amphtml_link_present = function() use ( $amphtml_url, $get_amp_html_link ) {
-			$this->assertEquals(
-				sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
-				$get_amp_html_link()
-			);
+		$assert_amphtml_link_present = function() use ( $amphtml_url, $get_amp_html_link, $available ) {
+			if ( $available ) {
+				$this->assertEquals(
+					sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
+					$get_amp_html_link()
+				);
+			} else {
+				$this->assertNotEquals(
+					sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
+					$get_amp_html_link()
+				);
+				$this->assertStringStartsWith( '<!--', $get_amp_html_link() );
+			}
 		};
 
 		$this->go_to( $canonical_url );
@@ -323,15 +366,73 @@ public function test_amp_add_amphtml_link_reader_mode( $canonical_url, $amphtml_
 		$assert_amphtml_link_present();
 	}
 
+	/**
+	 * URLs to test amphtml link.
+	 *
+	 * @return array
+	 */
+	public function get_transitional_mode_amphtml_urls() {
+		$providers = [
+			'is_home'         => static function () {
+				return [
+					home_url( '/' ),
+					add_query_arg( amp_get_slug(), '', home_url( '/' ) ),
+					true,
+				];
+			},
+			'is_404'          => static function () {
+				return [
+					home_url( '/no-existe/' ),
+					add_query_arg( amp_get_slug(), '', home_url( '/no-existe/' ) ),
+					true,
+				];
+			},
+			'is_post'         => function() {
+				$post_id = $this->factory()->post->create();
+				return [
+					get_permalink( $post_id ),
+					amp_get_permalink( $post_id ),
+					true,
+				];
+			},
+			'is_skipped_post' => function() {
+				$skipped_post_id = self::factory()->post->create();
+				add_filter(
+					'amp_skip_post',
+					static function ( $skip, $current_post ) use ( $skipped_post_id ) {
+						if ( $current_post === $skipped_post_id ) {
+							$skip = true;
+						}
+						return $skip;
+					},
+					10,
+					2
+				);
+				return [
+					get_permalink( $skipped_post_id ),
+					amp_get_permalink( $skipped_post_id ),
+					false,
+				];
+			},
+		];
+		return array_map(
+			function( $provider ) {
+				return [ $provider ];
+			},
+			$providers
+		);
+	}
+
 	/**
 	 * Adding link when theme support in transitional mode.
 	 *
-	 * @dataProvider get_amphtml_urls
+	 * @dataProvider get_transitional_mode_amphtml_urls
 	 * @covers ::amp_add_amphtml_link()
-	 * @param string $canonical_url Canonical URL.
-	 * @param string $amphtml_url   The amphtml URL.
+	 *
+	 * @param callable $data_provider Provider.
 	 */
-	public function test_amp_add_amphtml_link_transitional_mode( $canonical_url, $amphtml_url ) {
+	public function test_amp_add_amphtml_link_transitional_mode( $data_provider ) {
+		list( $canonical_url, $amphtml_url, $available ) = $data_provider();
 		AMP_Options_Manager::update_option( 'theme_support', AMP_Theme_Support::TRANSITIONAL_MODE_SLUG );
 		$this->accept_sanitization_by_default( false );
 		AMP_Theme_Support::read_theme_support();
@@ -343,11 +444,19 @@ public function test_amp_add_amphtml_link_transitional_mode( $canonical_url, $am
 			return get_echo( 'amp_add_amphtml_link' );
 		};
 
-		$assert_amphtml_link_present = function() use ( $amphtml_url, $get_amp_html_link ) {
-			$this->assertEquals(
-				sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
-				$get_amp_html_link()
-			);
+		$assert_amphtml_link_present = function() use ( $amphtml_url, $get_amp_html_link, $available ) {
+			if ( $available ) {
+				$this->assertEquals(
+					sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
+					$get_amp_html_link()
+				);
+			} else {
+				$this->assertStringStartsWith( '<!--', $get_amp_html_link() );
+				$this->assertNotEquals(
+					sprintf( '<link rel="amphtml" href="%s">', esc_url( $amphtml_url ) ),
+					$get_amp_html_link()
+				);
+			}
 		};
 
 		$this->go_to( $canonical_url );
@@ -358,22 +467,24 @@ public function test_amp_add_amphtml_link_transitional_mode( $canonical_url, $am
 		$this->assertEmpty( $get_amp_html_link() );
 		remove_filter( 'amp_frontend_show_canonical', '__return_false' );
 		$assert_amphtml_link_present();
+		$this->assertEquals( $available, AMP_Theme_Support::is_paired_available() );
 
-		// Make sure that the link is not provided when there are validation errors associated with the URL.
-		$invalid_url_post_id = AMP_Validated_URL_Post_Type::store_validation_errors(
-			[
-				[ 'code' => 'foo' ],
-			],
-			$canonical_url
-		);
-		$this->assertNotInstanceOf( 'WP_Error', $invalid_url_post_id );
-		$this->assertContains( '<!--', $get_amp_html_link() );
-		$this->assertTrue( AMP_Theme_Support::is_paired_available() );
+		if ( $available ) {
+			// Make sure that the link is not provided when there are validation errors associated with the URL.
+			$invalid_url_post_id = AMP_Validated_URL_Post_Type::store_validation_errors(
+				[
+					[ 'code' => 'foo' ],
+				],
+				$canonical_url
+			);
+			$this->assertNotInstanceOf( 'WP_Error', $invalid_url_post_id );
+			$this->assertContains( '<!--', $get_amp_html_link() );
 
-		// Allow the URL when the errors are forcibly sanitized.
-		add_filter( 'amp_validation_error_sanitized', '__return_true' );
-		$this->assertTrue( AMP_Theme_Support::is_paired_available() );
-		$assert_amphtml_link_present();
+			// Allow the URL when the errors are forcibly sanitized.
+			add_filter( 'amp_validation_error_sanitized', '__return_true' );
+			$this->assertTrue( AMP_Theme_Support::is_paired_available() );
+			$assert_amphtml_link_present();
+		}
 	}
 
 	/**
diff --git a/tests/php/test-class-amp-theme-support.php b/tests/php/test-class-amp-theme-support.php
index f2e5eb2ee58..1513d49aacd 100644
--- a/tests/php/test-class-amp-theme-support.php
+++ b/tests/php/test-class-amp-theme-support.php
@@ -323,6 +323,32 @@ public function test_finish_init() {
 		$this->assertEquals( 20, has_action( 'wp_head', 'amp_add_generator_metadata' ), 'Expected add_hooks to have been called' );
 	}
 
+	/**
+	 * Test that attempting to access an AMP post in Reader mode that does not support AMP.
+	 *
+	 * @covers AMP_Theme_Support::finish_init()
+	 */
+	public function test_finish_init_when_accessing_singular_post_that_does_not_support_amp() {
+		$post          = $this->factory()->post->create();
+		$requested_url = get_permalink( $post );
+		$this->assertEquals( AMP_Theme_Support::READER_MODE_SLUG, AMP_Theme_Support::get_support_mode() );
+		$this->assertTrue( post_supports_amp( $post ) );
+		add_filter( 'amp_skip_post', '__return_true' );
+		$this->assertFalse( post_supports_amp( $post ) );
+
+		$redirected = false;
+		add_filter(
+			'wp_redirect',
+			function ( $url ) use ( $requested_url, &$redirected ) {
+				$this->assertEquals( $requested_url, $url );
+				$redirected = true;
+				return null;
+			}
+		);
+		$this->go_to( amp_get_permalink( $post ) );
+		$this->assertTrue( $redirected );
+	}
+
 	/**
 	 * Test that attempting to access an AMP page in Reader Mode for a non-singular query will redirect to the non-AMP version.
 	 *