How to handle a resignation notice when leaving for a competitor?

I just accepted a significantly better offer at a company located nearby in the same industry. The company sits somewhere between being a current strategic partner (B2B supplier/distribution relationship) but ultimately will move towards being a direct competitor in the future.

My current boss is the best person I’ve ever worked for. We’re friends and hang out outside of work. We’ve talked a lot about my career goals and trajectory, so I don’t think at all he would find it a bad move for me and I’d be missed on the team greatly. I’m not at all concerned about this conversation strictly between him and myself, but ultimately I know it’s his responsibility to report anything up the chain.

I’m looking for advice on how to handle the possibility of him directly asking me (even in a curious supportive way) in my upcoming plan to give notice where I’m going. No non-compete clauses strictly apply here, but I’m concerned he’d be forced to lock me out and place me on leave immediately if finding out im leaving for a “competitor” in any way. I’m leaning towards something like “I’m not really comfortable sharing that at the moment, and would just like to focus on transitioning all of my duties currently, but once I’ve settled in I’d love to grab a drink and talk more.”

Any thoughts or advice here? Thanks