Third person - Lean feature using current anim setup?

I’ve looked up tutorials on a lean left/right feature for a third person character setup. However, these tutorials often include the mixamo skeleton or are tailored for first person.

What I would like to do is to use the current default anims (Thirdperson run/idle) and have a dynamic system where you can run/walk and the character simply leans left or right and the upper skeleton leans as you’re idle or running.

Could anybody point me in the right direction? Is it possible to just clone the third person anims and then in the character skeleton just simply rotate spine01? Or is there a cleaner way to do this?

Thank you