I previously purchased the bundle through How do I activate my subscription on Paramount+?

If you subscribe to SHOWTIME and Paramount+ through SHOWTIME  and you have not yet activated your subscription on Paramount+, you should cancel your existing SHOWTIME streaming subscription through SHOWTIME and subscribe to the new "Paramount+ with SHOWTIME" plan through Paramount+.

You will then be able to stream both SHOWTIME and Paramount content through the Paramount+ app or website.