Rivers smokes pot on reality show

Comedienne Joan Rivers stunned TV viewers in the U.S. on Tuesday by smoking marijuana on her reality show.

The veteran funnywoman was shown obtaining medicinal cannabis from a dispensary in California before puffing it from a pipe while sitting in her car with a pal.

As the effect of the drug takes hold, she then dissolves into fits of giggles and has to be driven home by a friend - stopping on the way to pick up burgers and fries.

But Rivers' pot-puffing antics infuriated her daughter Melissa, who told viewers, "My 78-year-old mother has now become 17, and I have become a soccer mum yelling at her teenage kid."

The scenes were broadcast on network WETV's reality show Joan & Melissa: Joan Knows Best.