diff --git bp-members/bp-members-functions.php bp-members/bp-members-functions.php
index 2158c2f..3e2b4b6 100644
--- bp-members/bp-members-functions.php
+++ bp-members/bp-members-functions.php
@@ -1434,15 +1434,19 @@ function bp_core_validate_blog_signup( $blog_url, $blog_title ) {
 }
 
 function bp_core_signup_user( $user_login, $user_password, $user_email, $usermeta ) {
-	global $bp;
+	global $bp, $wpdb;
 
-	// We need to cast $user_id to pass to the filters
-	$user_id = false;
+	// We need to cast $user_id & $signup_id to pass to the filters
+	$user_id = $signup_id = false;
 
 	// Multisite installs have their own install procedure
 	if ( is_multisite() ) {
 		wpmu_signup_user( $user_login, $user_email, $usermeta );
 
+		if ( ! empty( $wpdb->insert_id ) ) {
+			$signup_id = $wpdb->insert_id;
+		}
+
 	} else {
 		// Format data
 		$user_login     = preg_replace( '/\s+/', '', sanitize_user( $user_login, true ) );
@@ -1480,7 +1484,7 @@ function bp_core_signup_user( $user_login, $user_password, $user_email, $usermet
 			'meta'           => $usermeta,
 		);
 
-		BP_Signup::add( $args );
+		$signup_id = BP_Signup::add( $args );
 
 		if ( apply_filters( 'bp_core_signup_send_activation_key', true ) ) {
 			bp_core_signup_send_validation_email( $user_id, $user_email, $activation_key );
@@ -1489,7 +1493,7 @@ function bp_core_signup_user( $user_login, $user_password, $user_email, $usermet
 
 	$bp->signup->username = $user_login;
 
-	do_action( 'bp_core_signup_user', $user_id, $user_login, $user_password, $user_email, $usermeta );
+	do_action( 'bp_core_signup_user', $user_id, $user_login, $user_password, $user_email, $usermeta, $signup_id );
 
 	return $user_id;
 }