diff --git a/CHANGELOG.md b/CHANGELOG.md
index c4ea5bf45d..b44f6fa690 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ This is an alpha version! The changes listed here are not final.
 - Social | Fix publicize error in the editor due to malformed connections data
 
 ### Other changes <!-- Non-user-facing changes go here. This section will not be copied to readme.txt. -->
+- Comments API: Add wpcom_id and wpcom_login fields to comment author responses when requested via author_wpcom_data parameter.
 - Deprecate Jetpack geo location module
 - Fix the rendering of jetpack google fonts font faces for classic themes.
 - Forms: fixed default editor stying for textarea
diff --git a/class.json-api-endpoints.php b/class.json-api-endpoints.php
index 794bd049d6..1bdbe1ef25 100644
--- a/class.json-api-endpoints.php
+++ b/class.json-api-endpoints.php
@@ -6,7 +6,9 @@
  */
 
 use Automattic\Jetpack\Connection\Client;
+use Automattic\Jetpack\Connection\Manager;
 use Automattic\Jetpack\Status;
+use Automattic\Jetpack\Status\Host;
 
 require_once __DIR__ . '/json-api-config.php';
 require_once __DIR__ . '/sal/class.json-api-links.php';
@@ -771,6 +773,8 @@ public function cast_and_filter_item( &$return, $type, $key, $value, $types = ar
 					'is_super_admin' => '(bool)',
 					'roles'          => '(array:string)',
 					'ip_address'     => '(string|false)',
+					'wpcom_id'       => '(int|null)',
+					'wpcom_login'    => '(string|null)',
 				);
 				$return[ $key ] = (object) $this->cast_and_filter( $value, $docs, false, $for_output );
 				break;
@@ -1521,6 +1525,24 @@ public function get_author( $author, $show_email_and_ip = false ) {
 			$author['site_visible'] = $site_visible;
 		}
 
+		// Only include WordPress.com user data when author_wpcom_data is enabled.
+		$args = $this->query_args();
+
+		if ( ! empty( $id ) && ! empty( $args['author_wpcom_data'] ) ) {
+			if ( ( new Host() )->is_wpcom_simple() ) {
+				$user                  = get_user_by( 'id', $id );
+				$author['wpcom_id']    = isset( $user->ID ) ? (int) $user->ID : null;
+				$author['wpcom_login'] = $user->user_login ?? '';
+			} else {
+				// If this is a Jetpack site, use the connection manager to get the user data.
+				$wpcom_user_data = ( new Manager() )->get_connected_user_data( $id );
+				if ( $wpcom_user_data && isset( $wpcom_user_data['ID'] ) ) {
+					$author['wpcom_id']    = (int) $wpcom_user_data['ID'];
+					$author['wpcom_login'] = $wpcom_user_data['login'] ?? '';
+				}
+			}
+		}
+
 		return (object) $author;
 	}
 
diff --git a/json-endpoints/class.wpcom-json-api-list-comments-endpoint.php b/json-endpoints/class.wpcom-json-api-list-comments-endpoint.php
index 1239030228..993e14303c 100644
--- a/json-endpoints/class.wpcom-json-api-list-comments-endpoint.php
+++ b/json-endpoints/class.wpcom-json-api-list-comments-endpoint.php
@@ -161,33 +161,37 @@ public function __construct( $args ) {
 		$this->query = array_merge(
 			$this->query,
 			array(
-				'number'       => '(int=20) The number of comments to return.  Limit: 100. When using hierarchical=1, number refers to the number of top-level comments returned.',
-				'offset'       => '(int=0) 0-indexed offset. Not available if using hierarchical=1.',
-				'page'         => '(int) Return the Nth 1-indexed page of comments.  Takes precedence over the <code>offset</code> parameter. When using hierarchical=1, pagination is a bit different.  See the note on the number parameter.',
-				'order'        => array(
+				'number'            => '(int=20) The number of comments to return.  Limit: 100. When using hierarchical=1, number refers to the number of top-level comments returned.',
+				'offset'            => '(int=0) 0-indexed offset. Not available if using hierarchical=1.',
+				'page'              => '(int) Return the Nth 1-indexed page of comments.  Takes precedence over the <code>offset</code> parameter. When using hierarchical=1, pagination is a bit different.  See the note on the number parameter.',
+				'order'             => array(
 					'DESC' => 'Return comments in descending order from newest to oldest.',
 					'ASC'  => 'Return comments in ascending order from oldest to newest.',
 				),
-				'hierarchical' => array(
+				'hierarchical'      => array(
 					'false' => '',
 					'true'  => '(BETA) Order the comment list hierarchically.',
 				),
-				'after'        => '(ISO 8601 datetime) Return comments dated on or after the specified datetime. Not available if using hierarchical=1.',
-				'before'       => '(ISO 8601 datetime) Return comments dated on or before the specified datetime. Not available if using hierarchical=1.',
-				'type'         => array(
+				'after'             => '(ISO 8601 datetime) Return comments dated on or after the specified datetime. Not available if using hierarchical=1.',
+				'before'            => '(ISO 8601 datetime) Return comments dated on or before the specified datetime. Not available if using hierarchical=1.',
+				'type'              => array(
 					'any'       => 'Return all comments regardless of type.',
 					'comment'   => 'Return only regular comments.',
 					'trackback' => 'Return only trackbacks.',
 					'pingback'  => 'Return only pingbacks.',
 					'pings'     => 'Return both trackbacks and pingbacks.',
 				),
-				'status'       => array(
+				'status'            => array(
 					'approved'   => 'Return only approved comments.',
 					'unapproved' => 'Return only comments in the moderation queue.',
 					'spam'       => 'Return only comments marked as spam.',
 					'trash'      => 'Return only comments in the trash.',
 					'all'        => 'Return comments of all statuses.',
 				),
+				'author_wpcom_data' => array(
+					'false' => 'Do not add wpcom_id and wpcom_login fields to comment author responses (default)',
+					'true'  => 'Add wpcom_id and wpcom_login fields to comment author responses',
+				),
 			)
 		);
 	}