Use ps5 camera on ps4?

I would like to play Just Dance 2021 with my sister at Ps4 and for that I would need a camera in order not to buy a Playstation Move, which we don't want either, as we would like to play hands-free! Now I thought it would be easier to buy the Ps5 camera and then play with it! But is that even possible? Or do I have to buy the old Ps4 camera extra used?

No, unfortunately it doesn't work.