Darren Criss' father has died.

The former 'Glee' star took to Instagram to reveal his dad, Bill Criss, 78, has sadly passed away after coping with a rare heart condition for ''many years''.

Darren wrote: ''Bill Criss has left the building. After many years of coping with a rare heart condition - which, true to his form, very few would have even been aware of - he finally checked out peacefully yesterday morning, surrounded by his loved ones.

''Dad lived an extraordinary life. Anyone who ever met Bill Criss adored him instantly. He could talk to anyone about anything. Well-read and well-traveled, he made the world a better place wherever he went. (sic)''

The 33-year-old actor praised his dad for being an ''outstanding father'' and a ''true gentleman through and through''.

Darren added: ''He was as deliriously charming as he was relentlessly selfless; always putting other people first, making anybody who ever got into a conversation with him genuinely feel like they were the most incredible person in the room.

''And although he would have been the first to gracefully protest it, the simple truth is that he was in fact, every inch the exemplary man: a devoted husband, an outstanding father, a loving grandparent.

''He lived his days the same way he loved his friends and family - with an unwavering sense of composure, compassion, generosity, and humility.

''He was a true gentleman through and through, and was a constant source of joy and inspiration for me.

''I've spent most of my life trying to be like him, wanting to see and do all the incredible things he did - and I'm so grateful he was around to see me actually pull a few off.

''He was there for the greatest moments of my life, which of course, he always dressed up for. His kind blue eyes, big laugh, and infamous warm smile could not have been a better representation of who he was to his core.

''I cherished him every day, and will forever.''