John Travolta "didn't want to wake up" following the death of his son.

The 'Saturday Night Fever' actor's 16-year-old son Jett passed away in January 2009 after suffering a seizure and the 59-year-old star - who also has 13-year-old daughter Ella and three-year-old son Benjamin with wife Kelly Preston - says the tragedy was "the worst thing that's ever happened in my life."

Speaking to Barry Norman at a Q&A session in London Sunday night, he added: "The truth is, I didn't know if I was going to make it.

"Life was no longer interesting to me, so it took a lot to get me better."

The 'Pulp Fiction' star credited his controversial faith Scientology for helping him overcome the tragedy, saying the organization have "saved his life" on more than one occasion.

He said: "I will forever be grateful to Scientology for supporting me for two years solid, I mean Monday through Sunday.

"They didn't take a day off, working through different angles of the techniques to get through grief and loss, and to make me feel that finally I could get through a day."

Also during the fan-attended live interview, Travolta was presented with a cake in the shape of an airplane to mark his forthcoming 60th birthday and some audience members were invited onto the stage for a dance lesson.