“We started filming in March 2014, so it took a bit longer to get going, as it always does,” Timlett tells PEOPLE. “By the time we got started, we kept wondering, ‘Oh, is Robin Williams still going to be interested?’ “
Williams was the first major talent to sign on to the project, which was written and directed by Jones’ dad, Monty Python legend Terry Jones. The script had been sitting in Terry’s desk for years, and was based on the H.G. Wells’ book The Man Who Wrote Miracles.
The story revolves around an ordinary man named Terry who gets endowed with special powers by a group of eccentric aliens, who then place bets on how he’ll use his newfound abilities. Williams lends his voice to Neil’s best friend, Dennis the Dog. Production hit a roadblock when Bruce Almighty came out in 2003 with the similar “man-gets-special-powers” theme, so the filmmakers decided to put the idea on hold for awhile.
Yet every time Terry emailed Williams to make sure he was still interested, the Mrs. Doubtfire star always replied, “Yep, still in!”
Once Simon Pegg signed on to play Neil in December 2013, Terry told Williams the project was a go. Shortly afterwards, Timlett and Jones went over lines with him via Skype, and later, Jones and his dad flew out to San Francisco to record with Williams in a studio.
“I think Robin might have been a little nervous meeting dad,” Jones tells PEOPLE. “You’ve got legends in the room here. The guys in the recording studio were very happy to be working with the two of them.”
The session marked the first time Williams and Terry had worked together. “Robin kept calling Terry ‘Boss.’ Every time dad gave him directions he’d say, ‘Yes, Boss,’ ” Jones remembers with a laugh.
When the session ended, the Joneses were waiting for their taxi to the airport when they got a phone call from a frantic Williams. “About an hour before we got our taxi to the airport, we were having a beer and dad gets a phone call from Robin Williams,” Jones explains. “And he says, ‘I need to redo it, I need to redo it!’ “
Williams had an epiphany: “I’ve just got the idea, I just got what the character of Dennis is! He’s a 13-year-old boy. So everything I do, I just need to think of it like a 13-year-old boy.”
The Joneses agreed, and when they flew back to London, they rerecorded the session. “Two days later we did another Skype call and we recorded it all over again, and that’s what’s in the movie,” Jones says. “He nailed it. It was just so funny that we flew all that way and then scrapped it all.”
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Just a few months later, Williams took his own life. “It was a big shock really,” Timlett says. “I mean obviously during the time we were working with him we had no idea. We were very happy that we were able to finish his lines.”
“Obviously it was just shocking and devastating,” Jones adds. “And then working with his voice was a bit strange. You’d be walking along and you’d hear him and it was just this constant reminder.”
After Williams’ death, Timlett says he felt pressure to do the actor’s performance justice. “I think definitely the pressure came on to make sure we could do the best Dennis we could do,” he says. “The voice was great, but we just wanted to make sure that the way the dog looked made you really believe that Dennis was talking as a 13-year-old boy version of Robin Williams.”
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“It was definitely humbling and touching to work on it, and we just tried to do the best we could,” Jones adds. “It’s a shame to me that he didn’t get to see it, because I think he would have loved Dennis.”
In another sad twist following the completion of the film, Jones’ dad Terry began suffering from dementia. “Yeah that’s another sad thing,” Jones says. “He’s gotten to a place where he seems to feel quite content in the world he’s in. So you’ve got to look for the small things and to try to make him happy that way.”
Absolutely Anything hits theaters Friday.