Jason Momoa is to make a guest appearance in 'The Simpsons'

The Simpsons ex ecutive producer Al Jean revealed: "He is the celebrity that shows up and talks about this legend of this saint who was ground up and martyred and became the origin of modern-day pistachio ice cream. He tells this very gruesome story - and then Patty and Selma want him to sign their boobs and he runs away."

And it wasn't that easy for Jason to make some time in his schedule to come to do his voice work that was "within the terrestrial realm".

He told Entertainment Weekly: "We would hear, 'Oh, he's filming on a top of a mountain or he's filming under the water.' It was hard to get him in a studio that was within the terrestrial realm."

And Jason isn't the only Hollywood star to be making an appearance on the animated show as 'Better Call Saul's Bob Odenkirk will also be making his debut on the programme as a lawyer.

Al Jean said of the character: "He charges by the minute so he speaks...really...slowly. He just wants money for talking to Fat Tony.

"Homer is the mark because he's got such a big butt so he's a good target for pickpocketing. Fat Tony is arrested but he didn't do it - and he has to find out who did do it."