Harrison Ford is mourning the loss of his Star Wars costar Carrie Fisher

Harrison Ford is mourning the loss of his Star Wars costar Carrie Fisher.

“Carrie was one-of-a-kind…brilliant, original,” he said in a statement to PEOPLE. “Funny and emotionally fearless. She lived her life, bravely…My thoughts are with her daughter Billie, her mother Debbie, her brother Todd, and her many friends. We will all miss her.”

Get push notifications with news, features and more.

Fisher, 60, was aboard an 11-hour flight from London to Los Angeles on Friday when she went into cardiac arrest. Paramedics removed her from the flight and rushed her to a nearby hospital, where she was treated for a heart attack. She later died in the hospital.

She revealed in her latest book The Princess Diarist that she and Ford had a whirlwind love affair on the set of the 1977 Star Wars film.

Image zoom Mary Evans/LUCASFILM/Ronald Grant/Everett

“It’s been 40 years!” the actress previously told PEOPLE about spilling the secret of the real-life love between Han Solo and Princess Leia. “I didn’t say anything to anybody for years but it’s not like anyone’s deeply affected by it anymore.”

After stumbling upon her old, often angst-ridden journals that she kept while filming on location in London, Fisher felt the time had come to open up about the formative experience.

“It was so intense,” she previously explained to PEOPLE. “It was Han and Leia during the week, and Carrie and Harrison during the weekend.”

Image zoom Lucasfilm Ltd.

Their romance might have bene passionate, but their costar Mark Hamill was none the wiser.

The 65-year-old actor, who played Luke Skywalker — brother to her Princess Leia in the Star Wars films — recently told Entertainment Tonight that he was “blissfully unaware” of the Fisher-Ford fling.

“I was so self-involved at that point, they could’ve been doing it in front of me and I wouldn’t have noticed,” he joked. “I was single and had my own agenda.”

Image zoom Sunset Boulevard/Corbis via Getty Images

Hamill was one of the many stars leading prayers for Fisher on Twitter as news broke of her health.

“As if 2016 couldn’t get any worse… sending all our love to @carrieffisher,” he wrote.

Family spokesman Simon Halls released a statement to PEOPLE on behalf of Fisher’s daughter, Billie Lourd:

“It is with a very deep sadness that Billie Lourd confirms that her beloved mother Carrie Fisher passed away at 8:55 this morning,” reads the statement.