Larry Hagman, who spent more than a decade playing TV villain JR Ewing has died at the age of 81, his family says.
Hagman, who had suffered from cancer and cirrhosis of the liver, died in hospital on Friday afternoon, according to a family statement.
"Larry was back in his beloved Dallas, re-enacting the iconic role he loved most," said the family. "He was surrounded by loved ones."
Long-time friend Linda Gray, who played Sue Ellen, was by his bedside.
"Larry Hagman was my best friend for 35 years," said Ms Gray in a statement released by her agent.
"He was the Pied Piper of life and brought joy to everyone he knew. He was creative, generous, funny, loving and talented and I will miss him enormously.
"He was an original and lived life to the full."
Original cast member Victoria Principal, who played Pam Ewing, said Hagman had been "bigger than life, on-screen and off".
"He is unforgettable, and irreplaceable, to millions of fans around the world, and in the hearts of each of us, who was lucky enough to know and love him."
During 13 years as the most scheming oil tycoon in Dallas, JR in his Stetson became one of the most distinctive faces on television screens across the world.
It quickly became one of the network's top-rated programmes - with its 356 episodes being seen by an estimated 300 million people in 57 countries - and was revived this year.