diff --git a/addons/website/static/src/snippets/s_website_form/000.js b/addons/website/static/src/snippets/s_website_form/000.js
index 9411761857d..119d2a4f5cb 100644
--- a/addons/website/static/src/snippets/s_website_form/000.js
+++ b/addons/website/static/src/snippets/s_website_form/000.js
@@ -336,13 +336,21 @@
             // force server date format usage for existing fields
             this.$el.find('.s_website_form_field:not(.s_website_form_custom)')
             .find('.s_website_form_date, .s_website_form_datetime').each(function () {
+                const inputEl = this.querySelector('input');
+
+                // Datetimepicker('viewDate') will return `new Date()` if the
+                // input is empty but we want to keep the empty value
+                if (!inputEl.value) {
+                    return;
+                }
+
                 var date = $(this).datetimepicker('viewDate').clone().locale('en');
                 var format = 'YYYY-MM-DD';
                 if ($(this).hasClass('s_website_form_datetime')) {
                     date = date.utc();
                     format = 'YYYY-MM-DD HH:mm:ss';
                 }
-                form_values[$(this).find('input').attr('name')] = date.format(format);
+                form_values[inputEl.getAttribute('name')] = date.format(format);
             });
 
             if (this._recaptchaLoaded) {