irule help

Hi Experts, my requirement is to make https://www.example.com to be directed to https://example.com. Both URLs are owned by us but the www.example.com gives a certificate warning as the CN in the certificate issued is example.com.

In other words what will be an irule that when it sees "www.example.com" in the http request header, it redirects to https://example.com?

thnx