diff --git a/addons/web/static/src/legacy/xml/web_calendar.xml b/addons/web/static/src/legacy/xml/web_calendar.xml
index 75982842616..9d184e64006 100644
--- a/addons/web/static/src/legacy/xml/web_calendar.xml
+++ b/addons/web/static/src/legacy/xml/web_calendar.xml
@@ -12,7 +12,7 @@
     </div>
 
     <t t-name="calendar-box">
-        <div t-att-style="typeof color === 'string' ? ('background-color:' + color) + ';' : ''" t-attf-class="#{record.is_highlighted ? 'o_event_hightlight' : ''} #{typeof color === 'number' ? _.str.sprintf('o_calendar_color_%s', color) : 'o_calendar_color_1'} #{record.is_hatched ? 'o_calendar_hatched o_calendar_hatched_' + (typeof color === 'number' ? color : 1): ''} #{record.is_striked ? 'o_calendar_striked o_calendar_striked_' + (typeof color === 'number' ? color : 1): ''}">
+        <div t-att-style="typeof color === 'string' ? ('background-color:' + color) + ';' : ''" t-attf-class="o_event #{record.is_highlighted ? 'o_event_hightlight' : ''} #{typeof color === 'number' ? _.str.sprintf('o_calendar_color_%s', color) : 'o_calendar_color_1'} #{record.is_hatched ? 'o_calendar_hatched o_calendar_hatched_' + (typeof color === 'number' ? color : 1): ''} #{record.is_striked ? 'o_calendar_striked o_calendar_striked_' + (typeof color === 'number' ? color : 1): ''}">
             <span t-if="showTime" class="fc-time"/>
             <div class="o_event_title" t-esc="record.display_name"/>
             <div t-if="showLocation and record.location" t-esc="record.location"/>