diff --git a/wp-includes/blocks.php b/wp-includes/blocks.php
index 5fa7f1d6d0..aebb4b4065 100644
--- a/wp-includes/blocks.php
+++ b/wp-includes/blocks.php
@@ -373,6 +373,10 @@ function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
 		if ( ! isset( $metadata['style'] ) ) {
 			$metadata['style'] = "wp-block-$block_name";
 		}
+		if ( current_theme_supports( 'wp-block-styles' ) && wp_should_load_separate_core_block_assets() ) {
+			$metadata['style']   = (array) $metadata['style'];
+			$metadata['style'][] = "wp-block-{$block_name}-theme";
+		}
 		if ( ! isset( $metadata['editorStyle'] ) ) {
 			$metadata['editorStyle'] = "wp-block-{$block_name}-editor";
 		}
diff --git a/wp-includes/blocks/index.php b/wp-includes/blocks/index.php
index 51cf0c91e8..f9ffa411af 100644
--- a/wp-includes/blocks/index.php
+++ b/wp-includes/blocks/index.php
@@ -55,6 +55,29 @@ function register_core_block_style_handles() {
 		$files = glob( __DIR__ . '/**/**.css' );
 	}
 
+	$register_style = static function( $name, $filename, $style_handle ) use ( $includes_path, $includes_url, $suffix, $wp_styles, $files ) {
+		$style_path = "blocks/{$name}/{$filename}{$suffix}.css";
+		$path       = $includes_path . $style_path;
+
+		if ( ! in_array( $path, $files, true ) ) {
+			$wp_styles->add(
+				$style_handle,
+				false
+			);
+			return;
+		}
+
+		$wp_styles->add( $style_handle, $includes_url . $style_path );
+		$wp_styles->add_data( $style_handle, 'path', $path );
+
+		$rtl_file = str_replace( "{$suffix}.css", "-rtl{$suffix}.css", $path );
+		if ( is_rtl() && in_array( $rtl_file, $files, true ) ) {
+			$wp_styles->add_data( $style_handle, 'rtl', 'replace' );
+			$wp_styles->add_data( $style_handle, 'suffix', $suffix );
+			$wp_styles->add_data( $style_handle, 'path', $rtl_file );
+		}
+	};
+
 	foreach ( $core_blocks_meta as $name => $schema ) {
 		/** This filter is documented in wp-includes/blocks.php */
 		$schema = apply_filters( 'block_type_metadata', $schema );
@@ -67,32 +90,15 @@ function register_core_block_style_handles() {
 			$schema['editorStyle'] = "wp-block-{$name}-editor";
 		}
 
+		// Register block theme styles.
+		$register_style( $name, 'theme', "wp-block-{$name}-theme" );
+
 		foreach ( $style_fields as $style_field => $filename ) {
 			$style_handle = $schema[ $style_field ];
 			if ( is_array( $style_handle ) ) {
 				continue;
 			}
-
-			$style_path = "blocks/{$name}/{$filename}{$suffix}.css";
-			$path       = $includes_path . $style_path;
-
-			if ( ! in_array( $path, $files, true ) ) {
-				$wp_styles->add(
-					$style_handle,
-					false
-				);
-				continue;
-			}
-
-			$wp_styles->add( $style_handle, $includes_url . $style_path );
-			$wp_styles->add_data( $style_handle, 'path', $path );
-
-			$rtl_file = str_replace( "{$suffix}.css", "-rtl{$suffix}.css", $path );
-			if ( is_rtl() && in_array( $rtl_file, $files, true ) ) {
-				$wp_styles->add_data( $style_handle, 'rtl', 'replace' );
-				$wp_styles->add_data( $style_handle, 'suffix', $suffix );
-				$wp_styles->add_data( $style_handle, 'path', $rtl_file );
-			}
+			$register_style( $name, $filename, $style_handle );
 		}
 	}
 }
diff --git a/wp-includes/script-loader.php b/wp-includes/script-loader.php
index 8d9b54eb43..b6414350b7 100644
--- a/wp-includes/script-loader.php
+++ b/wp-includes/script-loader.php
@@ -2372,20 +2372,8 @@ function wp_common_block_scripts_and_styles() {
 
 	wp_enqueue_style( 'wp-block-library' );
 
-	if ( current_theme_supports( 'wp-block-styles' ) ) {
-		if ( wp_should_load_separate_core_block_assets() ) {
-			$suffix = defined( 'SCRIPT_DEBUG' ) && SCRIPT_DEBUG ? 'css' : 'min.css';
-			$files  = glob( __DIR__ . "/blocks/**/theme.$suffix" );
-			foreach ( $files as $path ) {
-				$block_name = basename( dirname( $path ) );
-				if ( is_rtl() && file_exists( __DIR__ . "/blocks/$block_name/theme-rtl.$suffix" ) ) {
-					$path = __DIR__ . "/blocks/$block_name/theme-rtl.$suffix";
-				}
-				wp_add_inline_style( "wp-block-{$block_name}", file_get_contents( $path ) );
-			}
-		} else {
-			wp_enqueue_style( 'wp-block-library-theme' );
-		}
+	if ( current_theme_supports( 'wp-block-styles' ) && ! wp_should_load_separate_core_block_assets() ) {
+		wp_enqueue_style( 'wp-block-library-theme' );
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ed631625f4..2bd99e4068 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-alpha-56063';
+$wp_version = '6.3-alpha-56064';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.