Joan Rivers' daughter Melissa is reportedly ''in denial'' over her mother's condition.

The 81-year-old comedienne is currently on life support after a cardiac arrest on Thursday (28.08.14), and the 46-year-old beauty may be forced to decide whether to switch off the machines next week but she's still adamant her mother will be able to pull through.

A source told the New York Daily News newspaper: ''She still thinks everything is going to be OK. She is refusing to admit that a world might exist without her mother in it. Others that are close to Joan are starting to realise that the outcome they want is very unlikely.''

Joan was placed in a medically-induced coma at Mount Sinai hospital in New York after she stopped breathing while undergoing a routine operation on her vocal cords at the Yorkville Endoscopy clinic.

Melissa caught a flight to New York as soon as she was informed of her mum's health scare.

She updated fans on Joan's condition on Friday (29.08.14) and thanked them for their continuous support over the past few days.

She said: ''Her condition remains serious but she is receiving the best treatment and care possible.

''We ask that you continue to keep her in your thoughts as we pray for her recovery.''