The pair shared the behind-the-scenes story of the sitcom's most famous blooper, which happened when Stiller — who died of natural causes at age 92 — made the cast laugh so hard, they couldn't continue the scene.
"Jerry Stiller always made us laugh. ... Jerry Stiller always knew his lines. But for some reason, he didn't have a lot of confidence in the fact that he knew his lines," recalled Alexander. "So he'd kind of get in his own way and they would come to him very sporadically and he would get angry with himself, as well, that they weren't coming quickly. That's where a lot of the internal rage of Frank Costanza would come from.
"It would make for some really funny line readings," added Alexander, who played Stiller's son, George, on the series.
Louis-Dreyfus interjected. "But also, Jason, this gesture that he did, where he would look to the sky a lot," she said, mimicking Stiller's frustrated pose. "This was him trying to remember the language, right?"
"Yeah, exactly. And he did that line on the first take — 'You saying you want a piece of me?'" Alexander said, imitating Stiller as Louis-Dreyfus began cracking up. "And you did exactly what you're doing now and I have to tell you when you (break character), very few people have the stamina to not go with you. There's something about your laugh that is just really infectious."
Infectious, indeed. Alexander recalled that after Louis-Dreyfus lost it, all the other actors did too. It took at least 15 minutes for them to shoot the scene correctly. "From that first reading, it gave us the giggles. And then you just couldn't face off against him. There's one take where you laugh, I fall off the bench I was sitting on," he said.
"I remember actually shortly after that (Jerry Seinfeld) went on 'The Tonight Show' or some late-night talk show and he brought that blooper reel — we had just shot it — to talk about what a professional organization he was running," Louis-Dreyfus said, laughing.
The "Veep" star honored Stiller on Monday by tweeting a video of the blooper. "The truth is that this happened all the time with Jerry Stiller," she wrote alongside it. "He was so funny and such a dear human being. We loved him."
Alexander shared his own tribute to the legendary funnyman, calling him "perhaps the kindest man I ever had the honor to work beside."
"He made me laugh when I was a child and every day I was with him. A great actor, a great man, a lovely friend," he added.