I'm going to lie to my mate about what time I'm going to the cinema
Why are you going to lie to your mate about what time you are going to the cinema?
No reason, I just feel like it.
Even if you want to go to the cinema alone, it is rude to mislead your friends. Instead of misleading him you should let him know you want to go alone.
To be honest I don't feel like interacting with anyone today.
Well if that is the case you should be honest about it. I think he will respect your wishes to be alone and you can plan on doing something else another day.