Let's just say right as Gibson was rounding the bases, doing that famous arm pump as he touched second base, Reiner and his future wife were deciding, right then, that they really, really liked each other.
"I'll never forget it," Reiner said while chatting with MLB.com host Jeremy Brisiel during the most recent episode of "Express Written Consent." "It was the first time we were ever ... together, and Kirk Gibson, I hate to say it, was the aphrodisiac."
How apropos, given Reiner's love for baseball, a fascination that began as a kid idolizing Willie Mays and the Giants. Reiner eventually transitioned into a Dodgers fan, the result of two life-changing events: 1) His family moved to Los Angeles when he was a teenager; and 2) Mays was shipped to the Mets, angering an angst-ridden Reiner, who switched allegiances to the Dodgers.
Regardless of who he's rooting for, baseball as a whole has always fascinated Reiner. He sees it as a metaphor for life. That part isn't all that unusual --we've heard many poetic philosophies over time that compare the basics of baseball to the basics of life.
But it's fun to hear it from one of the most creative minds in the entertainment industry, one who came up with countless memorable lines from a slew of unforgettable movie classics, from "When Harry Met Sally" to "Sleepless in Seattle" to "A Few Good Men," and on and on.
Leave it up to Reiner to give us a brand new perspective on this baseball-is-a-metaphor-for-life thing that we've not heard in the past.
"You go out into the world, just like a guy would go out and try to make a living," Reiner began. "You go into enemy territory, and then, you come home. And everyone says, 'Hey, he's home. He brought home the bacon.' And you're rewarded. They're happy to see you. Just like life."
Also, as is the case in life, Reiner philosophized, in baseball, you're part of a team, but "when you're at-bat, nobody can help you. You're all by yourself.
"It's like life in that we're alone, yet we're still part of a team. In other sports, you rely, always, on your teammates to help you in whatever it is you do. In baseball, yes, you rely on your teammates, but there are moments when you are along and no one can help you. That's very much like life, too."
This guy should be making movies.
Speaking of which, Reiner has a new one out. It stars two legends, Michael Douglas and Diane Keaton, and is about finding one more great romance in life. Reiner was inspired to do the movie, coincidentally, while he was promoting another one. He has Jack Nicholson to thank for that.
The two were promoting the 2007 smash hit "The Bucket List," and during one of the many press junkets, reporters would ask, "What's on your bucket list?" Nicholson said, "One more great romance."
"I thought, 'That's an idea for a film,'" Reiner said. Seven years later, Reiner's vision is hitting the theaters, titled, "And So It Goes."
Reiner has a small part in the movie, but, the director warns, you may not recognize him. That's because his normally shiny dome is covered in a hairpiece so fantastically crafted, it is, as he said, "virtually undetectable."
"I defy anyone to say, 'What happened to Rob?'" he continued. "Everybody knows I'm bald. I am bald. It's not a surprise. So when you see this, you'll go, 'Hey, who's that guy?' Because you cannot notice this hairpiece that's on me. It's impeccable."
[FYI: It's a terrible hairpiece.]
Reiner's humor, inherited from both of his parents, has served him well over the many decades since he left his Meathead role in the 1970s and went on to become one of the greatest directors of his generation.
He's also one of Hollywood's greatest baseball fans, as evidenced by the many ways the great game has found its way into his movies.
Baseball, as Reiner points out, is timeless.
"There's no end to it," Reiner said. "It could, conceivably, go on forever."
We can only hope for the same for Reiner.