diff --git a/client/my-sites/themes/theme-options.js b/client/my-sites/themes/theme-options.js
index <HASH>..<HASH> 100644
--- a/client/my-sites/themes/theme-options.js
+++ b/client/my-sites/themes/theme-options.js
@@ -59,6 +59,7 @@ const activate = {
 const activateOnJetpack = {
 	label: i18n.translate( 'Activate' ),
 	header: i18n.translate( 'Activate on:', { comment: 'label for selecting a site on which to activate a theme' } ),
+	// Append `-wpcom` suffix to the theme ID so the installAndActivate() will install the theme from WordPress.com, not WordPress.org
 	action: ( themeId, siteId, ...args ) => installAndActivate( themeId + '-wpcom', siteId, ...args ),
 	hideForSite: ( state, siteId ) => ! isJetpackSite( state, siteId ),
 	hideForTheme: ( state, theme, siteId ) => (
my-sites/themes/theme-options#activateOnJetpack: Add explanation about -wpcom suffix