Jerry Seinfeld has remembered the late Jerry Stiller as ''unbelievably funny''.

The late actor tragically passed away this week at the age of 92, and Seinfeld - who starred with Stiller on his eponymously titled sitcom - has recalled the moment he agreed to hire Stiller to play Frank, the father of George Costanza (Jason Alexander).

Seinfeld admitted he was originally unsure about the casting because Stiller wasn't ''bald'' like he'd envisaged Frank to be, but gave him a chance because 'Seinfeld' writer Larry Charles kept mentioning him.

He said: ''['Seinfeld' writer Larry Charles] kept saying, Jerry Stiller, Jerry Stiller. I remember Stiller and Meara from the '60s, but I hadn't seen Jerry in a while and I just didn't - and I thought, well, but he's not bald. But Larry just kept mentioning him and finally we brought him in.''

And after seeing Stiller in the role, Seinfeld admitted the casting was ''perfect'', because Stiller ''had the most amazing comedic stuff''.

He added: ''Those packages of just Jerry Stiller bits on my show are so unbelievably funny. What I loved about him is he so completes the George story. When you meet the father, you go, 'Oh, now I understand why he's like that.'

''It was the perfect finishing of the painting of George Costanza was Frank Costanza. He had the most amazing comedic stuff.''

Seinfeld was so happy with the casting, he gave Stiller free reign to put his own unique spin on the character, which yielded amazing results.

Speaking on Thursday's (14.05.20) edition of 'What a Joke with Papa & Fortune' on SiriusXM's 'Netflix Is a Joke Radio', he explained: ''We didn't know if he was planning it or it just came out that way, or he couldn't remember the line, or we didn't know what it was.

''We never gave Jerry Stiller a note. I never adjusted his performance once. Whatever he did, that's it. We're putting that out there. I don't know why he did it like that. I don't know why he screamed on that line. It doesn't matter. It's funny. So funny. I am such a dedicated believer in if it's funny, don't touch it. I don't care why it's funny. I don't care what the line was supposed to be. He said it that way, we're doing it that way.''

Stiller sadly passed away this week from ''natural causes'', and his death was confirmed by his son and fellow actor Ben Stiller.

Ben wrote on social media: ''I'm sad to say that my father, Jerry Stiller, passed away from natural causes. He was a great dad and grandfather, and the most dedicated husband to Anne for about 62 years. He will be greatly missed. Love you Dad.''