John Reilly has died.

Caitlin and John Reilly (c) Instagram

Caitlin and John Reilly (c) Instagram

The veteran actor - who was best known for his role as Sean Donely in 'General Hospital' - has passed away at the age of 64, his daughter Caitlin Reilly has revealed as she made a touching tribute to the "best person in the world.

The actress and TikTok star wrote on Instagram on Sunday (10.01.21) alongside a throwback photo of herself and her dad: "John Henry Matthew Reilly AKA Jack. The brightest light in the world has gone out. Imagine the best person in the world. Now imagine that person being your dad.

"I’m so grateful he was mine. I’m so grateful I got to love him. I’m so grateful I made it in time to hold him and say goodbye.

"I honestly don’t know what I’m going to do, but I know he’ll be with me. I love you forever Daddy."

Those working on the medical saga have been left "heartbroken" by the news.

A tweet from 'General Hospital's account read: "The entire General Hospital family is heartbroken to hear of John Reilly's passing. Our thoughts and prayers go out to his loved ones. Rest in peace. #GH."

His former castmates on the show have also paid tribute to the star.

Finola Hughes wrote: "There’s no room on Twitter to say how deeply one feels for a fellow actor & friend passing. I spent so many years in #JohnReilly ‘s company, suffice to say he was a huge influence on me and I am forever grateful for his kindness and love. My heart goes out to his family (sic)"

After sharing some classic clips from the show, she later added: "Such an outpouring of love for a wonderful man #JohnReilly In watching some of these clips the true essence of this kind, gifted, generous and fun loving soul really breaks through the screen. His comedic timing, his gravitas and his charisma are evident in every frame (sic)"

And McKenzie Westmore tweeted: "Heartbroken at the passing of my onscreen dad - John Reilly. May he Rest In Peace [crying, prayer and broken heart emojis] (sic)"

John - who is survived by Liz, Caitlin and two other daughters - began his career in the 1960s with roles in shows including 'Gunsmoke' and 'Death Valley Days', and in 1974, he replaced John Colenback as Dr. Dan Stewart in 'As the World Turns', before leaving in 1976.

He starred in 'General Hospital' from 1984 to 1995, making a return in 2013 and also had a guest role in spin-off 'General Hospital: Night Shift' in 2008.

He also had roles in movies such as 1979's 'The Main Event' and 'Gorp' in 1980.