How to create the "show in mail" link in Apple Calendar?

I'm wondering how can I make the "show in mail" link as seen in the photo below. Currently if i click a date in an email it will automatically create the link in the Calendar app. Can I do it manually for emails that don't contain dates?

How can I link associate a mail with an event in Calendar ? enter image description here


You can

  • Drag & drop a mail into the Calendar window to create a new entry with a link to the mail
  • Open an existing event in Calendar and drag&drop a mail into the "Notes, URL or attachments" field

PS: This may work for iCloud calenders only