King of pop Michael Jackson sparked health concerns after he appeared at a bookshop in a wheelchair.
The 49-year-old singer, who came to the Las Vegas bookshop along with his kids, was dressed in pyjamas and slippers and wheeled about by a minder.
Looking skinny and fragile, Jacko hid himself behind shades, a cap, black scarf and surgical mask.
"There are constant rumours of a Michael Jackson comeback but it was shocking to see that in reality he is a shadow of his former self," The Sun quoted an onlooker as saying.
"He seemed too weak even to get out of the chair to cross the road himself. He stayed in the store for two hours and wheeled himself around in the chair the whole time.
"The skin on his hands was peeling, almost like a snake's. He kept his mask on all the time. His security man was at his side and nobody approached him. It is really sad," the onlooker added.
Jacko was seen reading in the kids' section with children, Prince Michael, 11, Paris Katherine, ten, and five-year-old Prince Michael II, alias Blanket.
According to the sources, the singer often goes out in a wheelchair when he is too weak to walk.
"He has days when he is fine but others when he feels listless and too weak to walk. Then he calls for the wheelchair," a source said.
"Usually on those days he also refuses to get dressed, spending all day in his pyjamas," the source added.