The 72-year-old actress is busy promoting her new movie, Book Club, and appeared on Jimmy Kimmel Liveon Wednesday night. Keaton was quick to gush over her co-star and love interest in the film, Andy Garcia, quipping to Kimmel, "I like him better than you."
After Kimmel praised the 62-year-old actor for being "a very dashing man," Keaton was eager to discuss her final steamy scene with Garcia in Book Club.
"At the end of the movie, I have this extremely fun moment for me," she began. "I'm seeing Andy and we're together and I'm going to kiss him goodbye."
Keaton then got a nervous Kimmel out of his seat, but before she could proceed, the 50-year-old host had some questions.
"What's Andy's character's name in the movie? What's my motivation here?" he quipped. "I need something!"
"Nothing, you're just the man," Keaton assured Kimmel as the studio audience laughed.
After a slow start thanks to Keaton's hat getting in the way, the movie star planted a huge kiss right on the stunned Kimmel's lips.
"Oh my goodness. Well, a dream has come true for Jimmy Kimmel here," he said in awe. "Why can't I be Andy Garcia?"
The delight didn't end there, as Keaton had some notes for the host. "Andy's so great in the movie and he's so much fun to act with because he's very loose," she praised. "Unlike you. You were stiff!"
The love Keaton has for Garcia is clearly mutual. At the Book Club premiere last week, Garcia sang his co-star's praises.
"I love Diane Keaton, you know we're old friends. To me, she was on my bucket list to work with," he told ET's Kevin Frazier. "I've known her since the Godfather days. We've never really worked together, but we got to know each other, hanging out and stuff. She's one of those sublime actresses that we all want to work with. It was great when I heard this was happening. I threw my hat in the ring right away."
Check out the hilarity that ensued when ET caught up with Keaton and the rest of the Book Club ladies at CinemaCon: