The on-screen chemistry between Kirstie Alley and John Travolta may have lit up the screen in their 1989 hit movie "Look Who's Talking," but off-screen it was a different story, at least in the beginning.

Travolta, 59, it turns out, had a hard time being romantic when it came time to shoot his and Alley's character's first kiss. Instead, the "Grease" actor turned into a very, very famous diva.

Kirstie Alley Dishes on Patrick Swayze and Her 'Greatest Love'

"I turned into Barbra Streisand," Travolta recalled, while sitting alongside Alley in an interview with ABC News' Bianna Golodryga.

"He wouldn't be serious," Alley said. "You know, when you do a kissing [scene] it's hard enough, and he would start doing, would always say, 'Papa can you …'"

John Travolta Remembers James Gandolfini

"'Papa can you hear me,'" Travolta said, finishing Alley's sentence as he recited the line made famous by Streisand in the movie "Yentl."

Alley, 62, last year described Travolta, with whom she went on to star in two more "Look Who's Talking" movies and who shares her commitment to the Church of Scientology, as "the greatest love of my life," and said she fought off the impulse to "run off and marry" him.

"Believe me, it took everything that I had inside, outside, whatever, to not run off and marry John and be with John for the rest of my life," Alley told ABC News' Barbara Walters in November 2012.

Alley today said it was only the fact that she was married at the time, to Parker Stevenson, the former teen heartthrob of "The Hardy Boys" series, and father of her two children, that kept them apart.

"He is sort of the love of my live," Alley told Bianna Golodryga. "It's evolved into, you know, there was a time when I thought, 'Well, I can marry him,' and I was married."

"Of course, there's this one little glitch," she said of what, in her mind, kept them apart.

Travolta, now married to actress Kelly Preston, said he too felt the connection.

"I felt that love with Kirstie at a particular time," he said. "Kirstie was a person I could have fun with and play with. She's a playmate."

Alley, whose new show, "Kirstie," premieres Dec. 4 on TV Land, said the pair were able to move on without ever losing their close friendship.

"We had to evolve into friends, and now his wife is my best girlfriend," she said. "That's how it evolved, right?"

Moving on for Travolta and Alley meant also not forgetting the times the two shared the filming of the "Look Who's Talking" movies, including a dance scene in which Alley slapped Travolta.

"He's done all these movies, and he's an iconic dancer," Alley said of Travolta, whose "Saturday Night Fever" dance moves put him in the spotlight. "We were supposed to do a dance together, and I was real cocky and he goes, 'Look, which one of us has done these movies that there's dancing in?'"

"And I go, 'I don't care. I can dance with the best of them,'" she said. "I slapped him and, boom, I throw on my sunglasses."