Disney Studios Chairman Alan Horn said last week that Star Wars: Episode VII has already started filming and that casting is almost completed, but didn’t reveal much else.

Horn spoke to The Hollywood Reporter’s Stephen Galloway on April 2 at the Loyola Marymount University School of Film and Television in Los Angeles. He was invited as part of the Hollywood Masters series, which has involved such filmmakers as Alfonso Cuaron, Judd Apatow and David O. Russell.

Galloway mentioned that Horn is overseeing the production of Episode VII, as Disney now owns Lucasfilm. Horn confirmed what’s already known - that it will be taking place far after Return of the Jedi. As director J.J. Abrams likes to keep his productions under wraps, Horn didn’t go into specifics.

He did say that filming already started, but it’s not likely that Abrams has done any work with the main stars. Last month, Disney CEO Bob Iger said that filming would start in Pinewood in London in May.

As for the stars, “We have a lot of them [in place],” Horn said. “We’re just not completely done yet.” He refused to name names.

Horn did admit that there has been some issues with ironing out the screenplay, which is being re-written by Abrams and Lawrence Kasdan. Toy Story 3 writer Michael Arndt previously worked on the script and Horn acknowledged his work. When asked if the screenplay is where it needs to be before filming starts, he responded, “It actually is now.”

During the chat with Galloway, Horn also talked about his time as co-owner of Castle Rock and Warner Bros. president. While at Warner, Horn oversaw the Harry Potter franchise and hopefully that experience will help with Star Wars.

Episode VII opens in December 2015.