How to uninvite someone from a plan where you didn’t expect them to say yes ?

So I like this girl and I planned with her to go out for coffee…… while it isn’t a date I certainly am hoping it would be just us?

I did the mistake of speaking about this infront of a friend of mine and to not be rude invited him (I thought he wouldn’t come but he said yes)

Now I don’t want anyone to know yet that I like this girl, atleast yet……

How do I un-invite that friend …..

All help would be greatly appreciated…… thank you!