The Get Him to the Greek star was photographed leaving a yoga session in L.A. when he noticed the topless man sitting on a sidewalk and offered to help him out.
The man, identified only as 'Thomas', told Brand he wanted a burger, but the funnyman insisted on taking him home to cook him a more nutritious meal.
An onlooker tells British newspaper The Sun, "This guy Thomas was in a bad way. He'd been lying on the floor and talking to himself. On leaving the studio in his car, Russell noticed him there and was parked and out of the vehicle in no time to help. He asked the guy his name and what was wrong.
"I heard him offer to take him for some food. Thomas said he wanted a burger, to which Russell replied, 'You don't want any of that c**p, come to my house and you can have some proper food and a nice bath'."