Director Christopher Nolan and actor Matthew McConaughey made a surprise appearance at San Diego Comic-Con International.

The duo hosted a panel for their latest sci-fi film “Interstellar,” which is slated to hit theaters in November. Entertainment Weekly editor Matt Bean introduced the Hall H crowd to Nolan and McConaughey on July 24.

According to EW, McConaughey and Nolan refused to dish too many plot details to the crowd, but the film is about wormhole theories and how they effect time travel. McConaughey explained how he had to keep the project a secret to the Comic-Con crowd.

“I got a call from my agent who said Christopher Nolan has a film and he wants to meet,” McConaughey said, adding he met the director at his home for dinner. “three hours went by and he didn’t say anything about a new film or me having a role. Then a week later the script came.”

Nolan explained there was a lot of research done on wormhole theories before writing the script, according to EW. Physicist Kip Thorne, who was also an executive producer on the film, inspired the film.

“For me, in working on the script, there were a lot of very intense conversations with somebody who is much better informed than me. It actually made my head hurt a bit,” Nolan told the Comic-Con crowd. “I actually said to Kip, ‘Well, I don’t want to understand this stuff too much, because I have to be able to explain it to the audience.’ He’s a very generous collaborator, and somebody who has spent an incredible amount of time thinking about these concepts.”

Click here to read more about Nolan and McConaughey’s Comic-Con appearance. The film also stars Anne Hathaway, Jessica Chastain, Topher Grace, Michael Caine and more. “Interstellar” will premiere in theaters on Nov. 7.