Director Christopher Nolan is known to always be mum about plot details of the films he direct, and for the upcoming 'Interstellar' release date it is no different. Based on the latest trailer, the film is rumored to feature time travel as a major plot element.

The official synopsis of the movie tells the story of a group of explorers, led by McConaughey's character, Cooper, who find a 'wormhole' leading to unknown territories and which will "surpass limitations of interstellar voyage."

An official poster for the movie was released exclusively by Empire magazine showing McConaughey in a spacesuit walking on what seems to be terrain in outer space.

In a past interview, McConaughey spoke about his worries playing such a coveted role for the award-winning director, especially right after portraying such a difficult part in 'Dallas Buyers Club.'

"So going into a big movie I had a bit of fear, going like, 'Was it so much of a machine that I'm going to still be able to have an experience?,'" the actor said in an interview with HitFix.

"I'm serving his story but I'm still having a personal experience. And that was my biggest fear, or biggest trepidation going into it, but I have to say, I'm getting one out of it," added McConaughey.

In the film's latest trailer released just recently, McConaughey's character says a line that suggests time travel; an element that can possibly be a big aspect of the film.

"Our mission does not work if the people on Earth are dead by the time we pull it off," Cooper says in the trailer.

The line obviously suggests that Cooper and his crew are planning to jump space and time to possibly save the population of the Earth.

Watch the 'Interstellar' Trailer 4 below.