In the mid 90s I directed an English programme on Love Poetry starring Lily Savage. All was great, I thought, until I found Lily's agent hadn't passed her the script and she turned up to the studio with no idea what we were doing.
So, while her alter-ego got changed, we had an hour to sort out a solution. Autocue!
But in the end, even that wasn't necessary. Lily was such a great improvisor that we got the perfect performance from her with just a few cue cards and a bit of directing before each take.
It only goes to show that there are always solutions to difficult situations. And, finding out the skills and abilities of the person you are working with, before you start working with them, is always a good idea.