During a desperate battle, the Discovery is outgunned.
Saru - "Captain, the transporters and ventral shielding are offline (because those things always fail"
Nameless tactical officer - "Warp engines are off line and shields are down to 8 percent"
Saru looks at Captain George - "I've always loved you Captain"
George - "I love you too, with a squeeze of lemon and some sea salt . . . "
Micahel - "What the frack, I mean really?"
Detmer - "Captain, there's another Federation Ship coming in, its Federation, Constitution Class, we're being hailed"
This is Enterprise, Captain Christoper Pike Commanding, we've got this you bunch of idiots"
Then we see the NCC-1701 swooping in, it destroys 10 no 20 no 30 Klingons.
We know that the Enterprise is around because they talked out it in the one episode in a conversation between Stamets and Tilly.
So if they need a ratings boost, we're going to see Enterprise.
There's a good chance that we're going to see Spock as well.