Adding sys_contentexpirydate system field to content type

We have a requirement to setup scheduled archiving. For this, we need to use sys_contentexpirydate field. I do see this field available in the list of Shared and system fields.

However, under the Fields and Field sets table, I dont see this field. How do you add this field, so that it starts to appear in the content editor form?

thanks
Manvinder

Never mind…found it