Tenet and 5 other movies that were shrouded in secrecy

Christopher Nolan's new movie Tenet is highly mysterious, and the latest Tenet trailer has left us with lots of questions. Is it a time travel movie? What is time inversion? And how has the Inception director one-upped himself with a scene of a plane crashing into a building?

This is classic Nolan territory, withholding information to build peak interest. While we wait to see if Tenet will make its release date, here are five other films that were shrouded in total secrecy.

1. Cloverfield (2008)

Remember the devious marketing campaign for Matt Reeves' monster movie? It started well before Cloverfield's release in early 2008, managing to worm its way under people's skin, and sending the internet aglow with speculation.

The first bit of footage turned up in summer 2007, attached to Michael Bay's Transformers. There was no title, although it was evident the project had come from JJ Abrams' Bad Robot label, no stranger to secrecy following sensational TV hit Lost.

It turned out that the film eventually known as Cloverfield had actually been shot that same year. A variety of fake titles ('Slusho' and 'Cheese' being two of them) were used during production to put people off the scent. But that was just the beginning: it was the film's revolutionary viral marketing campaign that really got people talking.

Abrams and Reeves built an entire mythology around a movie no-one had yet seen. From fake MySpace pages (remember those?) to footage apparently showing the film's eponymous monster (none of which was used in the final product), Cloverfield got people taking and then some.

2. Under the Skin (2014)

Jonathan Glazer's extraordinary third feature tells the story of an alien serial killer in disguise. Scarlett Johansson is alluring and electrifying as the unnamed extraterrestrial who prowls the streets of Glasgow, seducing men before ultimately luring them to their doom in a manner both horribly nightmarish and fascinating.

Adapted from Michel Faber's novel, Under the Skin mixes and matches different filmmaking styles. The sequences alluding to Johansson's otherwordly origins, primarily the room of oil where her smitten victims sink to their death, deploy startling effects worthy of David Lynch at his surreal best. But there's a whole other side to the movie that demonstrates a more covert approach.

When Johansson's character selects her victims, she does so in a van, driving up next to a target of her choosing and drawing them in with her looks and guileless conversation. But did you know that the men she picks up weren't actors? In fact, they had no idea it was Johansson in disguise, and that there was camera equipment concealed in the vehicle.

Each of the men portraying Johansson's victims were unwittingly part of one of the weirdest, boldest, most brilliant science-fiction films of recent times. (Apart from neurofibromatosis sufferer Adam Pearson, who advised on his scene.) One assumes that some kind of clearance was needed to feature them in the final product – goodness knows what the reactions were.

3. 10 Cloverfield Lane (2016)

If Cloverfield was secretive, its eventual successor was even more so. The critically acclaimed 10 Cloverfield Lane actually started out life as a completely different project, which may ultimately have helped in keeping people off the scent.

The concept started as a low-budget spec script called The Cellar, which was eventually rewritten by Whiplash and La La Land filmmaker Damien Chazelle. It went into production in 2014 under Bad Robot with stars Mary Elizabeth Winstead and John Goodman on board.

The project went by the code name Valencia, but then the movie began to morph into something of a Cloverfield sequel, a "spiritual successor", in the words of producer JJ Abrams. "The spirit of it, the genre of it, the heart of it, the fear factor, the comedy factor, the weirdness factor, there were so many elements that felt like the DNA of this story were of the same place that Cloverfield was born out of," he explained.

Further gaslighting occurred in March 2015 when Winstead reiterated the premise of The Cellar, a young woman in a bunker in the wake of an apocalyptic disaster, without referring to the Cloverfield connection. The eventual reveal of the title in early 2016 was followed by a viral marketing campaign that sent everyone into a frenzy of expectation. Little wonder the ensuing movie was a box office hit: $110 million against a $15 million.

4. Unsane (2018)

In July 2017, Variety broke a news story that Out of Sight director Steven Soderbergh had shot a movie in secret. How could that be, particularly in this era of scrutiny? Well, Soderbergh managed it, and by shooting on an iPhone no less.

The film, the name of which Variety revealed as Unsane, broke new ground by shooting on an iPhone 7 Plus in 4K resolution, the latest experimental approach from a director who revels in such things. Not only had Soderbergh managed to keep production under wraps, but he'd also enlisted a big star: Claire Foy, hot off the success of The Crown.

Unsane, therefore, had an advantage in that it snuck up on people and was able to retain its sense of mystery. The movie was eventually revealed in February 2018, showcasing a fine performance from Foy as a young woman incarcerated in a mental institution against her will. In playing his cards close to his chest, Soderbergh gave the secretive Christopher Nolan a run for his money.

5. Avengers: Infinity War (2018)

Maintaining high levels of secrecy on a movie like Unsane is one thing. But how does one manage it during a gargantuan production like Avengers: Infinity War? The answer: with a lot of effort and collaboration between franchise owners Marvel, distributor Disney and directors Joe and Anthony Russo.

We all knew that the Marvel Cinematic Universe (MCU) was steadily building towards the battle to end all battles. Prior to Infinity War's release in April 2018, most of the principal MCU characters had their story arcs resolved in standalone movies, famously Iron Man/Tony Stark (Robert Downey Jr.) and Captain America/Steve Rogers (Chris Evans).

These standalone films had been interspersed with ensemble efforts like Avengers Assemble, but every single time, the heroic Avengers initiative had managed to see off their enemeiss. It was, therefore, clear that come 2018, 10 years into the MCU's history and with various actors' contracts up for renewal, that a shake-down was coming. And we knew that said threat would manifest in the form of Thanos (Josh Brolin), who had been teased during the post-credits reveal in 2012's Avengers Assemble.

Fiendishly, however, it was the nature of Thanos' threat that was craftily concealed from us. We all speculated until the cows came home about his harnessing of the Infinity Stones, but so well guarded was the movie that the bleak climax came as a jaw-dropping shock. The ear-splitting level of anticipation propelled the film to grosses of $2 billion worldwide. Questions then immediately began to mount as to how the Avengers would reverse the destruction in 2019's Avengers: Endgame, shot back to back with Infinity War.