"Carrie and I were attracted to one another, but I knew from previous jobs that it would have been a bad idea [to get involved with someone on set]," Hamill recalled. "But Carrie and I found pretexts."
"I remember one time -- I'm sure alcohol was involved -- we were talking about kissing techniques," he said. "I said: 'Well, I think I'm a fairly good kisser. I like to let the women come to me rather than be aggressive.' And she said: 'What do you mean?' Well, next thing you know we're making out like teenagers!"
Hamill said he and Fisher got hot and heavy during filming but ultimately didn't go farther than kissing.
"The one thing that drew Carrie and me back from the precipice was we kind of became aware of what we were doing and just burst out laughing," he shared.
Fisher was also involved with co-star Harrison Ford, who portrayed Han Solo, and detailed their affair in her memoir The Princess Diarist prior to her death in December 2016. Ford reacted to Fisher going public in the October issue of GQ.
"It was strange. For me," he confessed.
Hamill stars in the new Star Wars movie The Last Jedi, which marks Fisher's final appearance as Princess Leia. The film co-stars Daisy Ridley, Adam Driver and John Boyega, and opens in theaters Friday.