Ellen warns Seinfeld to hold onto his keys, and he doesn't listen.
The daytime talk show host and Seinfeld previewed the episode for the "Ellen DeGeneres Show" audience Tuesday, and played a moment when Ellen hid the keys to the very nice, classic car that was rented for the shoot.
"The keys are not in the car," Seinfeld said in the clip.
"See I told you you shouldn't leave the keys in the car," DeGeneres said.
Ellen waited for Seinfeld and the crew to start to squirm a bit before pulling the keys out from underneath the seat.
"It was to teach you a lesson and you should always -- I could have let that go longer," she said.
"I don't think that was going any place funny," Seinfeld said. But a second later he admitted, "That's funny."
"You just said it wasn't funny," Ellen responded in confusion.
"The way you did it was funny," Seinfeld clarified. "What you did was not funny."