"Seinfeld" had many guest stars during its nine-season run. While many of them succeeded in antagonizing the main characters in the universe, a few defenses actually got on the nerves of the real-life Jerry Seinfeld. Probably the most famous example is Seinfeld's feud with real-life 'Soup Nazi' but it was about the character's inspiration — noted soup chef Ali Yegane of Soup Kitchen International — being offended by the Seinfeld version rather than something Larry Thomas (who played the fictional Yev "Soup Nazi" Kasem) did. However, one particular star's cameo managed to get shoved right in Seinfeld's face ... literally.

In "Seinfeld's" season 5 two-parter "The Raincoats," Judge Reinhold memorably plays Aaron, Elaine's last boyfriend who has an unfortunate tendency to stand really close to people when he talks. During the appearance of "The Rich Eisen Show" Reinhold revealed that when they were rehearsing the scene, he couldn't help but notice that people looked like they were having a suspicious time when he was interacting with Seinfeld. That's because they, unlike Reinhold at the time, knew that the scene had really pushed the star away. Here's how Reinhold explained the situation:

“When I get to Jerry, I'm the closest, and then the crew was laughing in a way that looked like something was going on. hard when I get to Jerry?" And they said because he's such a germaphobe, he's terrified of what you're doing."

As anyone who watched the episode knows all too well, the knowledge that Jerry Seinfeld was genuinely disturbed by his character's close-talking did not deter Judge Reinhold in any way. In fact, as he was quick to mention in the interview, he somehow found a way to get even closer to the show's star when they were actually shooting the scene, making sure Seinfeld's terrified expression didn't require acting:

“So of course by the time he got to the camera I was almost touching his nose. I mean, the nose hairs were almost touching. I know he was so uncomfortable. If you see him again, you'll see that he's just crawling in his skin."

Many Seinfeld shows have interesting stories behind them. Philip Baker Hall says his life changed after playing Lieutenant Joe Bookmanthe library cop in "Seinfeld" Season 3, "The Library." At the other end of the spectrum, Bob Odenkirk Never Saw Seinfeld when he agreed to play Elaine's hapless medical boyfriend Ben in the Season 8 episode "Withdrawal." However, Reinhold himself can say that he spent a significant part of his appearance on the legendary sitcom in Jerry Seinfeld's personal space.