Christopher Nolan has made a surprise appearance at Comic-Con to introduce his upcoming sci-fi adventure Interstellar.

The Dark Knight director had not visited the fan event before, but excited fans welcomed him as part of Paramount's presentation, according to Empire.

He said: "I heard a lot about this being the place where people are most passionate about pop culture and movies. I thought it would be fun to come down and see what all the fuss is about."

Nolan has been keeping a tight lid on what Interstellar is actually about, but he did unveil a full-length trailer for the film which shows the Earth in a bad place as climate change escalates, with Matthew McConaughey and Anne Hathaway's characters going in search of another habitable planet.

The director said: "I grew up in a time when to be an astronaut was the highest ambition. The idea that we'd keep exploring space, pushing farther and farther out, seemed inevitable.

"I felt that had fallen off greatly over the past couple of decades. I really like the idea that we're on the cusp of a brand new era of exploration. I'm very much hoping that the experience we're putting together will take the audience on that ride."

He added vaguely of the film: "It's about human beings, what it is to be human and what our place is in the universe."

Nolan also referenced having had the help of theoretical physicist Kip Thorne, who studies the existence of wormholes, giving fans a further clue to what the plot might be.

Interstellar is due to be released in cinemas on November 6.