Sriram Raghavan says his upcoming thriller "Merry Christmas", starring Katrina Kaif and Vijay Sethupathi, is set in the early '80s and shares a thematic connection with the story of "Pinocchio".

Raghavan, regarded as the master of the thriller genre in India, returns to direction with the film after 2016's hit "Andhadhun" and hopes the audiences engage with the story that unfolds within a span of one night. It will hit the screens on January 12.

The trailer of "Merry Christmas" shows the two central characters walking past a theatre showing the children's classic "Pinocchio", about the titular wooden puppet whose nose grows longer when he lies.

"We have not specified the time but it is set in the early '80s. 'Pinocchio' has many movie versions so we decided to design our own version of the 'Pinocchio' poster. We haven't shown the movie on screen, you will only hear the soundtrack. So, thematically it's very much like our film because it is about deception. When Pinocchio tells lies, his nose gets longer," Raghavan told PTI in an interview.

The filmmaker said it was challenging to cut the trailer of the Hindi film as he wanted to create intrigue about the plot of the movie, which he shot simultaneously in Tamil.

"The Hindi trailer was more fun because it's got these quick cuts. The whole aim was to not give away the story and make viewers think of their own stories so that when they come to the cinema hall, they're surprised. Occasionally, one of them will be right too," he said.?

The Hindi trailer of "Merry Christmas" seems like a time capsule, taking viewers back to the era of weighing machines, landline phones and single-screen theatres.?

Raghavan, 60, said he decided to include these elements as they are all gone now.

"These are iconic things of that era and it has all gone now. I remember I would go to the railway station just to check my weight and get that little card, which had a picture and something written on it. I used to collect those. This is why we chose it for our film."

The idea to set the film within the span of a night was also by design, said the director, known for cult classics like "Ek Hasina Thi", "Johnny Gaddar", "Badlapur" and his biggest hit, "Andhadhun".

Raghavan said one of his earliest memories is watching Yash Chopra's 1969 thriller "Ittefaq", starring Rajesh Khanna and Nanda, which was also set in the course of a night.

"I think one-night stories are a genre in themselves because there can be all kinds of stories. I remember seeing Yash Chopra's 'Ittefaq' and I was completely blown away by that movie and performances. Even 'Die Hard' (the 1988 Hollywood hit featuring Bruce Willis) was a one night and a Christmas story.

"I like the sub-genre of one-night stories because it's tough to hold the attention of the audience. It's exciting to think how you are going to compress time and space, and make the story work," he added.

"Merry Christmas", according to the filmmaker, is an intimate story of two mysterious strangers.

"You meet them on this particular day. What they were doing before, how much of what they are saying is true or false, it is all left to you to make assumptions as a viewer. These two strangers are meeting each other and the viewer is meeting each of them, and we have to figure out, 'Okay, what's happening here?' It just makes you curious," he teased.

Just like his films, chance played an important role in the unique casting of Kaif and Sethupathi.

Kaif had once spoken to Raghavan about doing a film that is "out of her comfort zone" and that conversation stayed with him.

"It is unlike the films she has done so far which largely, and I'm saying largely, project her as a very glamorous person. She once met me two years back and said she would love to do something in this sort of a zone. Luckily, I found this story," he recalled.

The director said he was looking for an "oddball" pairing, but most of the suggestions that came up for the leading man seemed a bit too familiar.

"By chance, I met Vijay Sethupathi in Melbourne, where he was getting an award for 'Super Deluxe' and Tabu was getting an award for 'Andhadhun'. In the flight, it was fortuitous that I happened to see '96', starring Sethupathi, and then I landed and met the actor.

"I told him, 'I just saw your movie' and in my mind I kept thinking, 'What if this is the guy?' He's a Tamilian who speaks Hindi as he has lived in Dubai for three years. The language is not really alien to him," he said.

Raghavan said he kept thinking about Sethupathi and finally spoke to his team. Later, they also came onboard with the idea.

"This casting is so oddball that I hope it will create curiosity. You can't write chemistry on paper. Chemistry has to be performed and enacted. It has to come through. What they have managed is difficult to achieve."

For the Tamil version of "Merry Christmas", Raghavan said they came up with a "gibberish" version of Tamil for Kaif, who had to learn the language for the film.

"Luckily, she did the Hindi version first and then the Tamil version. So, she had gone through the experience and knew the emotions behind the scene and character, so she managed beautifully."