Hamill noted that the two had an instant connection upon first meeting on set of the first Star Wars movie, and even had a makeout session.
"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]. But Carrie and I found pretexts," said Hamill.
The actor continued, "I remember one time, I'm sure alcohol was involved, we were talking about kissing techniques. 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!"
In the 1977 original film, the duo shared an infamous kiss before it would turn out the characters were actually brother and sister.
"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. Which was unfortunate for me because the rocket launch sequence had been initiated," said Hamill.
While Fisher wrote in her last memoir about having a brief affair with her other co-star, Harrison Ford, while shooting 'Star Wars', Hamill admits he didn't know until after the fact that the two had a fling.
"Marcia [Lucas, Star Wars' editor and George Lucas's then wife] told me after we finished filming. I'm glad I didn't know before, as it probably really would have affected me. By the time I found out, I just thought it was hilarious. But you know men - even if we don't want to have a relationship, it's just in our nature to jockey for affection," explained Hamill.
'Star Wars: The Last Jedi' opens in theatres on Friday. (ANI)