Jason Alexander became 'furious and threatened to quit' Seinfeld after being left out of one of the sitcom's early episodes claims costar Michael Richards

Jason Alexander once threatened to quit Seinfeld when he felt his character, George Costanza, was not receiving enough screen time.

This claim about the 64-year-old actor was made in his former costar Michael Richards' upcoming memoir, Entrances And Exits, which is set to be published on June 4.

The 74-year-old actor - who recently revealed about his battle with prostate cancer - wrote that his castmate's outburst took place in 1991, while the show's cast was working on the third episode of its third season, entitled The Pen.

Richards recalled via Page Six that, while he accepted being left out of the episode with 'equanimity,' his castmate was incensed about the perceived slight.

The performer recalled: 'Jason threatens to quit after learning that he's also not in the episode. He's furious.'

Jason Alexander once threatened to quit Seinfeld when he felt his character, George Costanza, was not receiving enough screen time, claims Michael Richards in his upcoming memoir, Entrances And Exits; Jason seen in 2020

He then wrote that Alexander was under the impression that he would be one of the show's main draws. 

'Jason came onto the show with the most confidence of anyone. He had won a Tony Award on the New York stage... and until the table read for The Pen, he has assumed that Seinfeld is a buddy show, starring him and Jerry,' he recalled.

Richards added: 'This business breeds both massive egos and incredible insecurity, and this episode is one of those ego-jarring wakeup calls.'

The actor also wrote about an instance where he was also faced with humiliation after sitting through a table read for the season two episode The Chinese Restaurant, in which his character, Cosmo Kramer, was not featured. 

'I sit at the table without uttering a single word, and this is because not a single word has been written for Kramer,' he said.

The performer went on to write that Seinfeld's co-creator, Larry David, picked up on his disappointment and promised that he would never be put in a similar situation during the show's run.

Richards recalled that he feared for his career after he was not included in the show's first official cast shoot.

The comedian also wrote about how he did not expect his character to become a regular presence in the sitcom following the airing of its first truncated season.

The 74-year-old actor - who recently opened up about his battle with prostate cancer - wrote that his castmate's outburst took place in 1991, while the show's cast was working on the third episode of its third season, entitled The Pen

The news about the 64-year-old actor was revealed in his former costar Michael Richards' upcoming memoir, Entrances and Exits, which is set to be published on June 4; seen in April

Richards recalled via Page Six that, while he accepted being left out of the episode with 'equanimity,' his castmate was incensed about the perceived slight

He then wrote that Alexander was under the impression that he would be one of the show's main draws

He ultimately remained alongside Seinfeld, Alexander and Julia Louis-Dreyfus for the show's nine-season run, which lasted from 1989 until 1998.

Richards went on to win the Primetime Emmy Award for Outstanding Supporting Actor in a Comedy Series in 1993, 1994 and 1997 for his work on the show.

The performer was also nominated in the same category in 1995 and 1996.

Alexander was put up for the same award for his work on the program a total of seven times.