John Travolta’s greatest tragedy was losing his 16-year-old son Jett, who died in 2009 after suffering a seizure at his family vacation home in the Bahamas.

“It’s the worst thing that’s ever happened in my life,” the 64-year-old told Us Weekly Thursday. “The truth is, I didn’t know if I was going to make it.”

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A house caretaker found Jett unconscious in a bathroom after hitting his head. He was taken by ambulance to a Freeport hospital, where he was pronounced dead.

The teen, the oldest child of Travolta and his wife Kelly Preston, had a history of seizures.

Jett Travolta with father John. (Getty)

In 2003, Preston told Montel Williams that when Jett was 2 years old he became very ill before being diagnosed with Kawasaki disease, a condition that can cause inflammation of the arteries.

Travolta credited the Church of Scientology for helping him cope with the family tragedy.

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“The church never left our side for two years,” said Travolta. “I don’t know if I would have made it through without their support.”

The magazine revealed that Travolta and Preston continue to be devout followers.

Jett Travolta (Getty)

“Our church is the number one thing that keeps us grounded,” he stressed.

This isn’t the first time the movie star was candid about his faith. Back in 2014, he told UK’s Telegraph that despite his traditional Catholic upbringing, he identified with the controversial religion. The publication noted he was introduced to Scientology in 1975 by actress Joan Prather while on the set of “The Devil’s Rain” in Mexico.

“I wasn’t well and she gave me what’s called ‘an assist,’” he explained. “I got well very quickly after that, but I mean 30 minutes later.”

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According to the publication, Travolta became so intrigued by Scientology that he signed up for a course once he returned to Los Angeles.

U.S. actor John Travolta and wife Kelly Preston leave the court building in Nassau, Bahamas, Wednesday, Sept. 23, 2009. Travolta described the moments before his son's death in the Bahamas as he testified Wednesday against two people accused of trying to blackmail him with private information about the rescue effort. (AP Photo/Kris Ingraham)

Actor John Travolta and wife Kelly Preston in 2009. (AP)

“[Scientology] used everything I had always known to be true and provided really workable solutions,” he explained. “[Founder L Rob Hubbard] has done the heavy lifting for us and worked to hone down what works into a technology that helps you attain the things that you are looking for in a religion.”

Travolta insisted it was Scientology that helped him get through the period following Jett’s death.

“Oh my God, I don’t know what I would have done if I hadn’t had the support of Scientology,” he said. “I don’t think I could have got through it. They were with me every day after Jett died. They even traveled with me when I needed to get away. And for a solid two years, it was like that. It was only in the second year that I started to take a break of a day or two just to see how I was doing on my own.”

Scientology is the subject of former church member Leah Remini’s A&E docuseries “Scientology and the Aftermath.” The show, an Emmy winner, is currently on Season 3.

In late December 2018, the actress told Us Weekly she still receives threats for criticizing the faith.

Actor Leah Remini poses at the 2017 Creative Arts Emmy Awards in Los Angeles, California September 9, 2017. REUTERS/Danny Moloshok - RC13AF2AE270

Actress Leah Remini (Reuters)

Remini, 48, became a member of Scientology at age 9 but made her exit in 2013, Newsweek previously reported. In 2015 she released her memoir “Troublemaker: Surviving Hollywood and Scientology,” followed by her series a year after.

“They send out these attack dogs on social media,” claimed Remini to Newsweek. “Scientology hides behind the $3 billion they have with lawyers and social media. And they, too, are pretending they’re descenders of [the] First Amendment, freedom of religion and freedom of speech. And yet, they attack viciously anyone speaking out against the policies.”

Us Weekly pointed out that after a special episode about Jehovah’s Witnesses aired on Nov. 27, Scientologists blamed the show for inciting a string of arson attacks on that group in Washington state. While the first attack took place in March 2017, eight months before the special aired, the Church of Scientology insisted that reports of Remini looking into the Jehovah’s Witnesses were enough to incite hate.

The church said the actress “has made anti-religious bigotry her private cottage industry.”

The Associated Press contributed to this report.