He might be known as one of the most outrageously funny performers in Hollywood, but raising laughs on screen isn't something Jim Carrey takes lightly.

Susan Griffin catches up with the Hollywood star to find out why his films are like babies

Jim Carrey likes to compare himself to evolution. "I move slowly, but I definitely move," says the rubber-faced funny man, on why it's taken two decades for the follow-up to 1994's Dumb And Dumber to come to fruition.

"I was never planning on doing a sequel, but people never left me alone. They just kept after me, wanting to see another one, and then I watched it 10 years ago. I'd seen bits and pieces a number of times, but this time, I sat and watched it and was laughing. I couldn't believe some of the stuff we did.

"I was like, 'Gosh, I really like these guys, maybe the world needs them'. Plus the world leaders were calling me," he quips, wafting his hand around. "They said, 'There's unrest, we need your help'."

This is as animated as the 52-year-old, casually dressed in light cargo trousers, T-shirt and bomber jacket, with his hair standing on end, gets during our time together, which is something of a surprise, given his larger-than-life performances in the likes of Ace Ventura, Liar Liar and The Mask.

He might've been papped running around the city armed with a puppet of his co-star Jeff Daniels the night before, but today he's calm, quietly spoken, and listens intently to questions before giving thoughtful answers.

Peter Farrelly, who along with his brother Bobby directed the original and the sequel, describes Carrey as "a genius".

"More than people know," says Farrelly. "We sit down with him and go through the script line by line. It's unbelievable what he adds. Then, after we've shot the movie, we ask him to come into the edit room because he's so smart. I have the highest admiration for the man."

Carrey admits he had "lots" of input on the script. "I can't keep my hands off stuff and come up with as many insane things as I can possibly think of. I just spew and they go, 'Inappropriate... Appropriate'."

His work ethic comes from "being absolutely desperate to make something interesting happen in every scene".

"I have a lot of partners in crime with me on this one, particularly Pete and Bob, who are just a different ilk of people. They're the oddest leaders you'd ever want to follow," the actor explains.

"The Family Guy writers also jumped in for a while and had some fun with it. But a movie like this is not talking about what happens, it's about setting things up and playing them out to the fullest, so the audience say, 'I can't believe they're doing that'."

Fans of the original movie will know what to expect; a lot of slapstick and toilet humour. The idiotic Lloyd Christmas (Carrey) and Harry Dunne (Daniels) might be 20 years older but they're as daft as ever, this time criss-crossing the country to find the daughter Harry never knew he had.

The journey takes them from a mental institution, where Lloyd's been languishing in a 'comatose' state for 20 years, to a summit playing host to the world's most brilliant minds. Along the way, they bump into Fraida Felcher, 'the girl from Cranston' who was merely referenced in the first film but is brought to life by Kathleen Turner in the sequel.

"For me, having her on the set was a total honour, because she's done such incredible work over the years," says Carrey, who worked with the Oscar nominee on 1986's Peggy Sue Got Married.

Their on-screen meeting involves the cringe-inducing moment Lloyd refers to her character's 'blowfish jowls'.

"Having to say that to Kathleen Turner was very confronting for me," he admits with a goofy grin. "And a lot of people have said to me about the 'Excuse me sir' when she's under the hood of a car covered in grease. It gets big laughs."

They're just two of the many gaffes the pair make during the movie, but Carrey believes it's their innocence which makes them lovable, despite their foibles.

"There's no ego with them. They're completely authentic about their lives. It's like when you watch children, and you're relieved by the fact they're selfish at times and they cry when they want to and they laugh when they want to, and it's the same with these guys. It's the same kind of animal."

Born in Canada's Ontario, Carrey, who has a 27-year-old-daughter from his first marriage (he's been married twice), began his career as a stand-up comic in his teens. He moved to LA at 19 and became a regular at The Comedy Store, where he attracted the attention of comedy legend Rodney Dangerfield, and the pair started touring together.

He then moved onto TV and film with varied success, before 1994's Ace Ventura marked him out as a comedic tour de force.

His career hasn't all been about raising laughs, though - there have been plenty of dramatic roles too, notably 1998's The Truman Show, about a man who realises his entire life is being played out as a reality TV show, which earned him his first Golden Globe.

"I felt so lucky to be a part of that. I'd actually attempted to write something like The Truman Show two years before and couldn't quite find the handle. Then the script came to me and I was like, 'Oh, thank you God'," he says, putting his palms together.

"It's just the idea that to be your authentic self, you have to go into the abyss, the unknown, and trust that you're going to find the doorway," he says of the moment his character realises all is not as it seems and attempts to uncover the truth.

He won another Golden Globe for his portrayal of the comedian Andy Kaufman in 1999's Man On The Moon, and then in 2004, appeared in Eternal Sunshine Of The Spotless Mind, opposite Kate Winslet.

"It was one of those very rare moments where a writer and director capture a primal, human thing, which is the idea of being erased or wanting to erase someone. It was totally original." As was the script for 2009's I Love You Phillip Morris, in which he starred alongside Ewan McGregor.

"The fact a gay man would use the device of AIDS as an escape route? It was amazing to me that someone was doing that," says Carrey, who also wrote his first children's book in 2013.

He hasn't ruled out tackling another dramatic role in the future. "I hope to, sure," he says. "Those are the types of things where I like to wait for something special."

But comedy is where his heart is... Just don't ask him to pick a favourite film from his back catalogue.

"They're tough to choose between," he says, laughing. "They're like my kids."

EXTRA TIME - BEHIND THE SCENES

:: Production on Dumb And Dumber To began in September 2013 in Atlanta, Georgia, and Harry and Lloyd's old apartment was recreated over three weeks on a vacant lot in Cabbagetown.

:: Just 36 hours before cameras started rolling, Jeff Daniels was picking up an Emmy for his role in The Newsroom. "I went from winning that award, about a guy who's really smart, to playing a guy with an IQ of about 8," he notes.

:: Bird-loving Brady from flat 4C, played by Brady Bluhm who's now a teacher, makes a reappearance, after film-makers tracked him down on Facebook.

:: Rob Riggle appears as twin brothers Travis and Captain Lippincott, and was blown away with his first scene. "We were in a car and I was thinking to myself. 'I'm in a scene with Jim and Jeff, I'm the third guy!' It took a take or two to refocus!"

:: Kathleen Turner came on board after hearing that her character, Fraida, was described as a 'dressed-down Kathleen Tuner-type'. She says: "I thought I could do that..."

:: Dumb And Dumber To is released on Friday, December 19

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