Ricky Gervais loves to make people laugh and the press conference for his new film "The Invention of Lying" was no exception.

Arriving promptly at 10 a.m., the British funny man who is making his co-directorial debut with the film at TIFF, tells the roomful of journalists how rude it is to be late.

"Everyone look at your watch when they come in," he instructs reporters, in reference to how the rest of the cast, in particular Jennifer Garner, were stragglers.

He says he always arrives early and being late is one of his biggest annoyances.

"I can't believe anyone wouldn't rush to see me," says Gervais, to a roar of laughter.

Gervais, who created the much acclaimed BBC series "The Office" and HBO's "Extras," is certainly hoping people will rush to see his new film -- and find it funny.

Set in a world where lying doesn't exist and everyone says what's on their mind, one average Joe named Mark Bellison (Gervais) discovers he has the ability to tell a lie and uses it to gain fame, fortune and hopefully love.

Opening with a hilarious look at what would happen on a first date if you had to tell the honest truth ("He seems nice, a bit fat. No, I won't be sleeping with him tonight," says Garner's character Anna to her mom on a cell phone during the date), the movie also delves into deeper issues such as morality and religion.

"At no point did we say there definitely isn't a God in this world, we just say that we haven't thought about it or discovered it yet," says Gervais, who produced the film, and co-directed and co-wrote it with newcomer Matthew Robinson.

"Also, isn't it great if it does start a conversation?" says Garner. "Conversation can be controversial or not but religion is something work examining and faith is something worth questioning and talking about."

But Robinson says they had to draw the line somewhere.

"We had stuff on politics, we had stuff on race, we had things like that earlier but it asked more questions than it answered."

"We didn't want to bog people down with the details," adds Gervais.

The truth test

Gervais says the film addresses how a world without the ability to lie actually isn't as good as one where you can lie as the latter allows people to make moral decisions based on how the truth will be received. Gervais says he actually lies all the time -- but to protect people's feelings.

"'Can you come to my baby's christening?' I go, 'I can't I'm busy.' I don't say, 'Well that doesn't sound like a great day out,'" says Gervais.

"That's what makes you a nice member of the human race, that you can choose when to make a good lie."

Gervais says it's often easy to tell when someone is lying.

"I think you know deep inside when someone's being kind and when someone's being cruel or when someone's just being honest and that's why you surround yourself with people you trust. By definition you don't know whether you're gullible or not, you learn by your mistakes. I think you trust everyone once."

Gervais says he enjoyed directing his first movie alongside Robinson and was thrilled to be able to work with such a talented cast, which also features Rob Lowe, Tina Fey, Jason Bateman, Edward Norton and a cameo by Philip Seymour Hoffman.

It's not uncommon for Gervais to "break" (or ruin) a take because he's laughing so hard and he says this was definitely the case on this film.

"When someone says something funny, I laugh. Just because I heard the line 15 times before, or I even wrote it, it doesn't matter," says Gervais.

It caused a bit of frustration for the actors though, in particular for Garner, who says a lot of her good takes were ruined this way.

"He's encouraging you to improvise, you toss something out there and on top of your line in an unusable way he ruins the take with a cackle that is completely of another world," says Garner, who adds she couldn't stay mad for long as making Gervais laugh is like a badge of honour in itself.

"The Invention of Lying" opens in theatres Oct. 2nd.