Carrie Fisher regretted opening up about her affair with Harrison Ford, according to her brother Todd Fisher.

The 'Star Wars' actress - who tragically passed away in December 2016 at the age of 60 - revealed in her book 'The Princess Diarist' that she had enjoyed an affair with her co-star Harrison during the filming of the hit sci-fi movie franchise.

But in her brother Todd's new memoir 'My Girls: A Lifetime with Carrie and Debbie', he claims his sibling had been warned by their mother Debbie Reynolds - who died the day after Carrie - not to speak about the affair, and she eventually found out the hard way that her mother was right.

Todd wrote: ''Neither of them had any illusions that they had a future together. They were simply acting on a strong mutual attraction while making a movie together, as if that's not one of the oldest stories in Hollywood.

''What Harrison and everyone else may not know is that Carrie went to mom right after the book became such a big deal and said, 'You were right, I shouldn't have told that story.' For what it's worth, Harrison, she really did regret telling the story of that affair.''

Carrie first made the shocking revelation a month before her passing in November 2016, when she described the three-month affair as ''intense''.

She said: ''It was so intense. It was Han and Leia during the week, and Carrie and Harrison during the weekend.''

And Carrie also insisted she gave Harrison plenty of warning before publishing her tell-all book.

She said: ''I wouldn't have ambushed him like that, but it's still ... no matter if I told him or not, it probably feels like an ambush. It feels like an ambush to me, and I'm the one that wrote it.

''I said: 'I found the journals that I kept during the first movie and I'm probably going to publish them.' And he just sort of raised his finger and said, 'Lawyer!'''