One of the most memorable "Seinfeld" scenes almost didn't happen. 

In a recent interview, Jerry Seinfeld shared interesting tidbits about a fifth season episode, "The Marine Biologist." 

The episode concludes with a long, hilarious speech delivered by George Costanza, played by Jason Alexander. 

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The speech he gives is his telling of the story of how he saved a dying beached whale after he was sent into the ocean by Diane, a woman he was seeing who was under the impression he was a marine biologist and qualified to help. 

The speech, which includes many memorable "Seinfeld" lines like "At that moment, I was a marine biologist," "The sea was angry that day, my friends" and "I said easy big fella," was a last-minute addition, Seinfeld revealed in a recent interview. 

"I don’t know the schedule that week, but let’s say we’re shooting it on Wednesday. It’s Tuesday," Seinfeld said during an appearance on "The Rich Eisen Show." "We don’t have the golf ball goes into the blowhole of the whale. We don’t have it — it was never in the script."

Different plot points in that specific episode of the show include Jerry telling Diane that George was a marine biologist, Kramer hitting golf balls into the ocean at the beach and George and Diane taking a walk on the beach and coming across a crowd observing a dying whale in the water. 

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"It was the night before we shot the scene with Jason in the coffee shop," Seinfeld recalled. "I said to Larry [co-writer], ‘Hey, what if what puts the whale in distress is Kramer’s golf ball?’ He’s hitting golf balls at the beach. George is walking on the beach with the girl. We haven’t connected them. We saw no connection the night before. We write that speech the night before. Two o’clock in the morning.

"We show up the next day. We hand Jason, who’s an effing genius, we hand Jason that speech. How long is that speech? It’s a page, two pages." 

He recalled that he told Alexander he had a half hour to memorize the speech, which Alexander said was "no problem." 

The speech, which almost didn't happen, ended up being the most memorable of the episode and an all-time favorite among "Seinfeld" fans. Alexander was able to deliver the long speech in a single take, eliciting loud laughs from the live audience watching the story unfold. 

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"When Jason is doing the speech, this one shot, there’s one cut to me with my eyes. My eyebrows, I’m watching him. You think I’m reacting to the story. I’m reacting. ‘I can’t believe he’s getting this speech word perfect.’ That is what I’m thinking," Seinfeld said. 

"I’m not even in the scene. I’m not acting. I’m just watching Jason get the speech right in front of a live audience. OK, it’s not film. In film, movies, you screw it up and we’ll do it again. In TV, this live audience is going to hear this speech for the first time once. So, you want those juicy laughs. They’re hearing these jokes the first time, and he’s getting it perfect. That is why I have that look on my face in that scene."

The comedy of the scene doesn't end with George's speech. At the end, when he shared that he pulled a golf ball out of the blowhole of the whale, Jerry instantly looks at Kramer (Michael Richards), knowing it was his golf ball that was stuck in the whale's blowhole.

Richards delivers the hilarious line, "What is that a Titleist?" when he sees the golf ball.

Seinfeld said during the recent interview they had to wait the morning of shooting for the company's approval to use the name of the golf brand in the episode.