The death has been announced of veteran American television star Johnny Carson at the age of 79.

It is reported that he died from emphysema.

He had undergone a successful quadruple bypass operation in 1999.

Carson hosted NBC's "The Tonight Show" for nearly 30 years. 

He presented his final show on May 22 1992, seen by an estimated 55 million viewers, and was replaced by Jay Leno.

Carson was inducted into the Television Hall of Fame in 1987 and awarded the Presidential Medal of Freedom in 1992.