Friend gave his coworker my number without asking first. How do I let this guy down gently?

One of my friends was texting me about his coworker while he was at work. His coworker and I had a common interest in a specific show, and I was texting my friend some jokes about the show/some sarcasm that my friend was sharing with his coworker (I don’t really have a problem with people sharing my texts tbh). He ended up giving his coworker my number because he thought I was funny and he was interested in me. Why he didn’t give him my Instagram or ask me first I have no clue. Anyway, he ended up texting me like 20 minutes later with some stuff about the show we both like, but if I am being honest I have zero interest in dating in general. The guy seems nice and I don’t want to be a jerk to him (since he is my friends coworker too) but I have no clue what to say, if I should even say anything. If anyone has any suggestions on how to gently let this guy know I’m not really interested in anything that would be greatly appreciated!