Is this clematis beyond help?

[needhelpwiththisplease]

It was absolutely fine on Wednesday and has look like this since Thursday evening

Is it recently planted, or an established plant?

I'd just keep watering & see what happens...

It looks typical of Clematis wilt, a fungal problem, and happens quite dramatically. If it’s just one stem, best to cut it out completely, and dispose of the stem. It’s not usually fatal, and should recover, with other stems unaffected.

Info: https://www.notcutts.co.uk/garden-advice/problems-pests/clematis-wilt/

Is it armandii? Mine's done the same.

Clematis wilt. I have just lost two to this. Gave them up as a bad job and put in a disease resistant rose instead.
I have never had a montana wilt but other clematis varieties all seem susceptible.