James Gandolfini left 'The Sopranos' creator David Chase constantly mesmerised with his "otherworldly" eyes

David, 78, has now fondly remembered the star, telling a CBS News retrospective on the creation of the landmark show in honour of its 25th anniversary about his love for James' trademark looks on the series: "He's incredible. Well, the whole thing's about his face and about his eyes, actually. "There's something about his eyes that - it was otherworldly."

David also said the humour in the show was so prevalent he could has "never been able to figure out whether it's a comedy".

He added: "I guess it's like life. I don't know, I hope."

David previously told People he was glad the show's fanbase was still going strong, saying it left him with a "tremendous sense of gratitude".

He added: "I can't remember this happening with any other television show ever."

David also said about James' performance: "Look at the show, and there you see it. It's a cliché to call that stuff magic, but he was totally inhabiting that fictional creature.

"It's the best thing I've ever done. It's probably the best thing I ever will do."

James' co-star Edie Falco, who played his wife Carmela on the show for all six of its series, also told the CBS special she loved working on it so much she "couldn't stop crying" during the script read-through for 'The Sopranos' finale.

The 60-year-old 'Nurse Jackie' star said: "I really couldn't stop crying - it was ridiculous. It was, 'This thing in this moment will never happen again to me, to anyone.'"

The series finale is infamous for cutting to black as its lead character Tony Soprano - played by the late James Gandolfini - looks up at a door opening in a diner, leaving fans furious and puzzled over whether it meant he had been assassinated by a mob rival.

Edie also said she had a "alchemy" with her co-star James.

The mother-of-two Edie, who has never married, added: "We both had Italian families, had some idea of what this dynamic feels like, and just sort of fell into it with great ease.

"It was, you know, a 10-year marriage. And it was as close to a real one as I had known."