HELP! - How to treat a backstabbing ex colleague?

[NALondon]

(NA for this) We have a new male colleague starting tomorrow (let’s call him Ben). We worked together in a previous role at the time I thought there was mutual respect we both worked very hard and I respect him as a professional in his field, during this role I had a new manager and we didn’t see eye 2 eye. I was going through an extremely rough time as my new manager was trying to push me out anyway he could, Ben was aware of all of this.
The first glimmer of light in that VERY bad period was when I managed to find a new job. I was offered this job at interview!! 2 days later my offer was withdrawn I was devastated, it came to light Ben had said something negative to an old colleague as he had worked for this employer in the past.
Ben knew how bad things were for me, I don’t know if he intended to make things worse or not.. he’s quite arrogant and a typical investment banker!! He might have just run his loud mouth off as its a "lads" club as he very much plays up to that image….
Ben is joining the company I have worked at for over 2 years now, I very well respected and known for my work on a few things. Ben is already joining a very difficult team!! I will be shocked if he lasts the month!
Do I reach out in the morning to say hello or try and keep my distance.. our professional field is quite small, so his previous actions have really impacted my career.

[RandomMess]

Feed him to the wolves!!!

In reality like him dig his own grave whilst you keep your distance.

[Palavah]

Don't do anything proactive. Smile sweetly and do nothing that could be miscontrued by anyone who doesn't know the background. Be serene and enigmatic and keep your nose clean and pencil sharp and don't give him the satisfaction.

[NALondon]

I haven't said anything negative, to be honest, he's very good at his job.. It won't really matter in the team he's joining I have said in the past I wouldn't wish working in that team on my worst enemy hence I didn't say anything when I heard of his interview.
The only thing I insisted on was his NDA but I will ensure he doesn't understand enough of a particular product to try and replicate it everything he has been provided has software to track it just in case.