Kevin Hart enters the room and immediately shares his two rules.

"A, no eye contact, and B, no eye contact," he says with feigned seriousness - before bursting into laughter along with Will Ferrell, who is standing at his side.

In reality, the pair are about as far from being movie divas as you could imagine, but they're having fun playing up to the stereotypical behaviour that certain Hollywood stars are known for.

Their new film, Get Hard, also plays on stereotypes.

In the movie, Ferrell plays James, a millionaire hedge fund manager who's charged with fraud and given a 10-year-stretch behind bars, with 30 days to get his affairs in order first.

His main priority is toughening up, and so he turns, misguidedly, to the only person he believes can help him prepare for lock-up; Darnell (Hart), a struggling but ambitious small business-owner who he assumes has done time, given his age, economic circumstances - and "because he's black", notes 35-year-old Hart.

As offended as he is with James' presumptions, he decides if the man's ignorant enough to think that way, and willing to pay for mentoring, then he's going to take him up on the offer.

"Darnell assumes I'm a crook and a liar. I assume he's done jail time, and we learn we're completely wrong about each other," adds Ferrell, 47, who started out on the sketch show Saturday Night Live and is known to millions as Ron Burgundy, from the Anchorman movies.

"We're talking and approaching the stereotypes that have been out there for so long," continues Hart. "We're making people laugh at themselves. In this movie, you're looking at two people who judge each other because of the situation they're in, not just the colour of their skin."

Ferrell agrees. "The goal is just to make people laugh, but at the same time, weave in some satirical comedy along the way."

Their unlikely coupling harks back to movies like 1980's Stir Crazy, starring Gene Wilder and Richard Pryor.

"You can't do what those guys have done over again - just make a great movie for our generation and hopefully, people watch it, and think that's a great pairing for this time, this decade," offers Hart, who started out in stand-up and has also had roles in the likes of Grudge Match and The Wedding Ringer.

"You don't go into something thinking it's time for us to take over, be the next duo," he adds. "Both of us have an audience and a fan base, and this time they get to come together."

Hart clearly looks up to his co-star - and not just because he's a good foot shorter than 6ft 3in Ferrell (6ft 5in if you factor in that hair).

"I love to see a person taking his craft seriously. I soak it up, I'm a sponge," he says. "I don't want to think I'm the only one over here trying to bust my ass trying to get to a place. I wanna see the guys who have got to that place and are still doing it."

After soaking up the praise, Ferrell quips: "That said, I did get Kevin's trailer downsized. I feel terrible about that..."

California-born Ferrell came up with the idea for Get Hard with his producing partner Adam McKay.

"We were imagining what you would do if you're an upper middle-class person who's thrown into prison. How would you survive? Flee the country? Change your appearance? Or learn to survive in that world?"

The married father-of-three, who recently received a star on the Hollywood Walk Of Fame, has first-hand experience of life behind bars... sort of.

"I was in prison in the movie Elf. It felt real," he deadpans, referring to the 2003 Christmas classic in which he plays Buddy, a man raised as one of Santa's elves who moves to New York, with hilarious repercussions.

So who is the harder of Hart and Ferrell in real life?

Hart believes it's Ferrell. "I think Will has the crazy gene," he says.

The man in question doesn't disagree: "That's how I'd have to survive, just act completely crazy."

He'd have to leave his leather binder behind, though. The item continues to be a cause of mirth for Hart, who was surprised to see his co-star clasping the old-school organiser when they first met.

"The one big cultural stereotype is when a black guy gets money, you can tell, you can see it. Like, 'Oh my God, Kevin's doing a lot better now, look at his leather pants and diamond belt!'" says Hart, laughing. "Will [looks like he] might have worn a free T-shirt every day and his phone is from years ago. He doesn't give a s**t, and I love that about him."

So what's next for the pair?

"I'm about to do the remake of The Intouchables, which is more of a serious side [of me]," says Hart. "In the business, you take some risks here and there and mix it up."

And how about Ferrell?

"I was waiting on The Intouchables..." he says, straight-faced,"but recently found out the role has gone".

:: Get Hard is out in cinemas now

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